Oxidative Stress, Inflammation
Conditions
Keywords
organic diet, health, pesticides, inflammation biomarkers, oxidative stress biomarkers
Brief summary
The study aims to evaluate the hypothesized benefits of a systematic organic diet for children, over those of a conventional diet. The specific objectives of this study are to: i) Demonstrate the decreased body burden of pesticides for those children consuming an organic diet, and ii) Evaluate the effects in specific biomarkers of inflammation and oxidative stress in children systematically consuming an organic diet.
Detailed description
A single-blinded, randomised 2 x 2 cross-over study is conducted to evaluate the effect of a 40-day organic diet compared to a 40-day conventional diet on biomarkers of exposure (pesticides metabolites) and biomarkers of effect (oxidative stress/inflammation markers) in children. The study is approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2016/25) and the Cyprus Ministry of Education and Culture (7.15.06.15/2). Written informed consent for children to participate in the study is obtained from children's parents or legal guardians. Study participants are recruited from public primary schools in Limassol, Cyprus following communication with the school's headmaster. Each school that participates in the study is randomized to one of the two study arms; conventional-organic or organic-conventional. Participants' blinding is not possible since children know which diet they have at each phase. However, all documents and urine containers are coded, so that researchers are blinded to subjects' identity and group allocation. Participants provide 6 first morning urine samples during the duration of the study; 1 baseline sample, 2 samples in the conventional phase and 3 samples in the organic phase. Anthropometric measurements (weight, height, waist circumference) are taken at the beginning and end of the study by trained researchers at the school area. A baseline questionnaire is administered to parents at the beginning of the study through a telephone interview to collect information on demographic characteristics, pesticide use at household and children's activities. A food frequency questionnaire is administered to parents at the end of the conventional phase through a telephone interview to collect information about the food habits of the children during the 40-day conventional period. A food diary is given to parents at the beginning of the study and parents use it during the organic phase, to collect information about the compliance of the children to the organic dietary menu, the children's health status and the pesticide use at home. In order to encourage adherence to the organic diet menu, an event is organised during the organic phase of both groups, with activities for children and free sampling of organic food products. Descriptive statistics are used to summarize the demographic characteristics for participating children. Categorical variables are described as sample size and percentages, normally-distributed continuous variables as mean±SD and non-normal continuous variables as median and interquartile range (Q1-Q3) or the appropriate transformation is conducted, such as the log transformation. For testing whether characteristics of interest are different among groups the Student's t-test are utilized for continuous normally distributed variables and the chi-square test for categorical characteristics. For continuous data that are not normally distributed, the Wilcoxon non-parametric analysis is used instead or a transformation of the data is conducted first in order to meet the normality criterion. Linear mixed-effects models are used to account for the correlation among repeat urine samples collected from the same child and determine whether mean pesticide metabolite and biomarkers concentrations differ between the organic phase and the conventional phase.
Interventions
DIETARY_SUPPLEMENTOrganic diet
Full organic diet from certified organic products as obtained from certified producers and cooked by a certified organic restaurant. five meals each day delivered to students.
Sponsors
European Commission
Cyprus University of Technology
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Investigator)
Eligibility
Sex/Gender
ALL
Age
10 Years to 12 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy children aged 10-12 years, residing in Cyprus over the last five years who consume primarily (\> 80%) conventional food (non-organic).
Exclusion criteria
* Children with chronic conditions (e.g. diabetes, asthma) or allergies in food (e.g. gluten, lactose tolerance)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Pesticide Metabolite 3-phenoxybenzoic Acid (3-PBA) Levels in Urine Between Organic and Conventional Periods* | Last sample of the conventional period and the last sample of organic period, up to 40 days for each period | Percent change in pesticide metabolite 3-phenoxybenzoic acid (3-PBA) levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Overall Difference in Median 3-PBA Levels in Urine Between the Conventional and Organic Periods* | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | Overall difference in median 3-PBA levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Effect of Organic Treatment in 3-PBA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | A linear mixed-effect regression model was fitted for 3-PBA (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05. |
| Overall Difference in Median 6-chloronicotininc Acid (6-CN) Levels in Urine Between the Conventional and Organic Periods* | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | Overall difference in median 6-CN levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Effect of Organic Treatment in 6-CN Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period - Odds Ratio Calculated Based on the Fit of a Logistic Mixed-effect Model | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | A logistic model was fitted for 6-CN (binary variable; above and below LOD) due to the high number of values below LOD. The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Effect of Organic Treatment in 8-iso-PGF2a Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | A linear mixed-effect regression model was fitted for 8-iso-PGF2a (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05. |
| Change in Oxidative Stress/Inflammation Biomarker MDA Levels in Urine Between Organic and Conventional Periods* | Last sample of the conventional period and the last sample of organic period, up to 40 days for each period | Percent change in oxidative stress/inflammation biomarker MDA levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Change in Oxidative Stress/Inflammation Biomarker 8-OHdG Levels in Urine Between Organic and Conventional Periods* | Last sample of the conventional period and the last sample of organic period, up to 40 days for each period | Percent change in oxidative stress/inflammation biomarker 8-OHdG levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Effect of Organic Treatment in MDA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | A linear mixed-effect regression model was fitted for MDA (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05. |
| Overall Difference in Median MDA Levels in Urine Between the Conventional and Organic Periods* | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | Overall difference in median MDA levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Overall Difference in Median 8-OHdG Levels in Urine Between the Conventional and Organic Periods* | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | Overall difference in median 8-OHdG levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Effect of Organic Treatment in 8-OHdG Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | A linear mixed-effect regression model was fitted for 8-OHdG (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05. |
| Change in Oxidative Stress/Inflammation Biomarker 8-iso-PGF2a Levels in Urine Between Organic and Conventional Periods* | Last sample of the conventional period and the last sample of organic period, up to 40 days for each period | Percent change in oxidative stress/inflammation biomarker 8-iso-PGF2a levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
| Overall Difference in Median 8-iso-PGF2a Levels in Urine Between the Conventional and Organic Periods* | 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period | Overall difference in median 8-iso-PGF2a levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration. |
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Group 1 Schools in Group 1 began first with the organic period and continued with the conventional period.
The organic period was organized in two 20-day cycles with differences in the menu to allow for greater variety in the meals, so that the participants' compliance to the organic treatment would be enhanced. During the organic period, participants were asked to strictly follow the two 20-day organic dietary menus provided to them for a total of 40 days.
During the conventional period, participants were asked to maintain their usual dietary habits and choices (\>80% conventional diet) for a total of maximum 40 days. | 43 |
| Group 2 Schools in Group 2 began first with the conventional period and then switched to the organic period.
During the conventional period, participants were asked to maintain their usual dietary habits and choices (\>80% conventional diet) for a total of maximum 40 days.
The organic period was organized in two 20-day cycles with differences in the menu to allow for greater variety in the meals, so that the participants' compliance to the organic treatment would be enhanced. During the organic period, participants were asked to strictly follow the two 20-day organic dietary menus provided to them for a total of 40 days. | 106 |
| Total | 149 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| First Period (40 Days) | Withdrawal by Subject | 24 | 0 |
| Second Period (40 Days) | Withdrawal by Subject | 0 | 18 |
Baseline characteristics
| Characteristic | Group 1 | Group 2 | Total |
|---|---|---|---|
| Age, Continuous | 11.03 years STANDARD_DEVIATION 0.53 | 11.21 years STANDARD_DEVIATION 0.61 | 11.16 years STANDARD_DEVIATION 0.59 |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Sex: Female, Male Female | 14 Participants | 59 Participants | 73 Participants |
| Sex: Female, Male Male | 29 Participants | 47 Participants | 76 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 0 | 0 / 0 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
Change in Pesticide Metabolite 3-phenoxybenzoic Acid (3-PBA) Levels in Urine Between Organic and Conventional Periods*
Percent change in pesticide metabolite 3-phenoxybenzoic acid (3-PBA) levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: Last sample of the conventional period and the last sample of organic period, up to 40 days for each period
Population: The percent change was estimated only for the participants who completed the full course of the organic treatment, using the log-transformed, creatinine-adjusted biomarker levels.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Change in Pesticide Metabolite 3-phenoxybenzoic Acid (3-PBA) Levels in Urine Between Organic and Conventional Periods* | 11.4 % change |
Comparison: A one-sample t-test was used to assess whether the percent change was different than zero.p-value: <0.001One-sample t-test
Primary
Effect of Organic Treatment in 3-PBA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period
A linear mixed-effect regression model was fitted for 3-PBA (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Effect of Organic Treatment in 3-PBA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | -1.214 ng/g creatinine (log-transformed) |
p-value: <0.001Mixed Models Analysis
Primary
Effect of Organic Treatment in 6-CN Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period - Odds Ratio Calculated Based on the Fit of a Logistic Mixed-effect Model
A logistic model was fitted for 6-CN (binary variable; above and below LOD) due to the high number of values below LOD. The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Effect of Organic Treatment in 6-CN Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period - Odds Ratio Calculated Based on the Fit of a Logistic Mixed-effect Model | 0.651 Odds Ratio |
p-value: 0.014Mixed Models Analysis
Primary
Overall Difference in Median 3-PBA Levels in Urine Between the Conventional and Organic Periods*
Overall difference in median 3-PBA levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Overall Difference in Median 3-PBA Levels in Urine Between the Conventional and Organic Periods* | 2088 ng/g creatinine |
| Median 3-PBA Levels in the Organic Period | Overall Difference in Median 3-PBA Levels in Urine Between the Conventional and Organic Periods* | 576 ng/g creatinine |
Comparison: The overall differences in the medians of biomarkers between the conventional and the organic periods were assessed with the non-parametric Wilcoxon rank sum testp-value: <0.001Wilcoxon rank sum test
Primary
Overall Difference in Median 6-chloronicotininc Acid (6-CN) Levels in Urine Between the Conventional and Organic Periods*
Overall difference in median 6-CN levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Overall Difference in Median 6-chloronicotininc Acid (6-CN) Levels in Urine Between the Conventional and Organic Periods* | 26 ng/g creatinine |
| Median 3-PBA Levels in the Organic Period | Overall Difference in Median 6-chloronicotininc Acid (6-CN) Levels in Urine Between the Conventional and Organic Periods* | 20 ng/g creatinine |
Comparison: The overall differences in the medians of biomarkers between the conventional and the organic periods were assessed with the non-parametric Wilcoxon rank sum testp-value: 0.017Wilcoxon rank sum test
Secondary
Change in Oxidative Stress/Inflammation Biomarker 8-iso-PGF2a Levels in Urine Between Organic and Conventional Periods*
Percent change in oxidative stress/inflammation biomarker 8-iso-PGF2a levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: Last sample of the conventional period and the last sample of organic period, up to 40 days for each period
Population: The percent change was estimated only for the participants who completed the full course of the organic treatment, using the log-transformed, creatinine-adjusted biomarker levels.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Change in Oxidative Stress/Inflammation Biomarker 8-iso-PGF2a Levels in Urine Between Organic and Conventional Periods* | 1.6 % change |
Comparison: A one-sample t-test was used to assess whether the percent change was different than zero.p-value: 0.023One-sample t-test
Secondary
Change in Oxidative Stress/Inflammation Biomarker 8-OHdG Levels in Urine Between Organic and Conventional Periods*
Percent change in oxidative stress/inflammation biomarker 8-OHdG levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: Last sample of the conventional period and the last sample of organic period, up to 40 days for each period
Population: The percent change was estimated only for the participants who completed the full course of the organic treatment, using the log-transformed, creatinine-adjusted biomarker levels.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Change in Oxidative Stress/Inflammation Biomarker 8-OHdG Levels in Urine Between Organic and Conventional Periods* | 1.7 % change |
Comparison: A one-sample t-test was used to assess whether the percent change was different than zero.p-value: 0.167One-sample t-test
Secondary
Change in Oxidative Stress/Inflammation Biomarker MDA Levels in Urine Between Organic and Conventional Periods*
Percent change in oxidative stress/inflammation biomarker MDA levels between the last sample of the conventional treatment period (before the start of the organic treatment) and the last sample of organic treatment period. A one-sample t-test was used to assess whether the percent change was different than zero. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: Last sample of the conventional period and the last sample of organic period, up to 40 days for each period
Population: The percent change was estimated only for the participants who completed the full course of the organic treatment, using the log-transformed, creatinine-adjusted biomarker levels.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Change in Oxidative Stress/Inflammation Biomarker MDA Levels in Urine Between Organic and Conventional Periods* | 0.1 % change |
Comparison: A one-sample t-test was used to assess whether the percent change was different than zero.p-value: 0.913One-sample t-test
Secondary
Effect of Organic Treatment in 8-iso-PGF2a Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period
A linear mixed-effect regression model was fitted for 8-iso-PGF2a (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Effect of Organic Treatment in 8-iso-PGF2a Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 0.408 ug/g creatinine (log-transformed) |
Comparison: The interaction term for time and treatment was included in the models since it met the threshold of p-value\<0. 05. Specifically, for the interaction term of time and organic treatment b=-0.016, 95% CI=\[-0.023,-0.010\], p-value=\<0.001.p-value: <0.001Mixed Models Analysis
Secondary
Effect of Organic Treatment in 8-OHdG Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period
A linear mixed-effect regression model was fitted for 8-OHdG (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Effect of Organic Treatment in 8-OHdG Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | -0.119 ug/g creatinine (log-transformed) |
p-value: 0.014Mixed Models Analysis
Secondary
Effect of Organic Treatment in MDA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period
A linear mixed-effect regression model was fitted for MDA (log-transformed, creatinine-adjusted). The model accounted for the duration and the effect of treatment. It included student-level (repeated measures within person) and school-level (multiple students clustered within each school) random intercepts with an unstructured covariance matrix. Continuous variables, other than time (days of treatment), were centered at the population means. The model included fixed effects for treatment condition (organic or conventional) and time (days of treatment), where time = 0 was used for the start of the treatment. The model was adjusted for the baseline value (first urine sample for all children) of the outcome to account for the background participant levels. An interaction term for time and treatment was considered and subsequently dropped if it did not meet the threshold of p-value\<0. 05.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Effect of Organic Treatment in MDA Levels in Urine, Taking in Account the Repeated Measures and Duration of Organic Period | 0.189 umol/g creatinine (log-transformed) |
Comparison: The interaction term for time and treatment was included in the models since it met the threshold of p-value\<0. 05. Specifically, for the interaction term of time and organic treatment b=-0.016, 95% CI=\[-0.023,-0.010\], p-value=0.01.p-value: 0.001Mixed Models Analysis
Secondary
Overall Difference in Median 8-iso-PGF2a Levels in Urine Between the Conventional and Organic Periods*
Overall difference in median 8-iso-PGF2a levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Overall Difference in Median 8-iso-PGF2a Levels in Urine Between the Conventional and Organic Periods* | 2964 ug/g creatinine |
| Median 3-PBA Levels in the Organic Period | Overall Difference in Median 8-iso-PGF2a Levels in Urine Between the Conventional and Organic Periods* | 3028 ug/g creatinine |
Comparison: The overall differences in the medians of biomarkers between the conventional and the organic periods were assessed with the non-parametric Wilcoxon rank sum testp-value: 0.259Wilcoxon rank sum test
Secondary
Overall Difference in Median 8-OHdG Levels in Urine Between the Conventional and Organic Periods*
Overall difference in median 8-OHdG levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Overall Difference in Median 8-OHdG Levels in Urine Between the Conventional and Organic Periods* | 323 ug/g creatinine |
| Median 3-PBA Levels in the Organic Period | Overall Difference in Median 8-OHdG Levels in Urine Between the Conventional and Organic Periods* | 296 ug/g creatinine |
Comparison: The overall differences in the medians of biomarkers between the conventional and the organic periods were assessed with the non-parametric Wilcoxon rank sum testp-value: 0.07Wilcoxon rank sum test
Secondary
Overall Difference in Median MDA Levels in Urine Between the Conventional and Organic Periods*
Overall difference in median MDA levels between the conventional and organic periods. The overall differences in the medians of biomarkers between the conventional and the organic phase were assessed with the non-parametric Wilcoxon rank sum test on the creatinine-adjusted concentrations pooling all conventional samples (including the baseline) and the organic samples for all participants, regardless of the duration for which they followed the organic treatment. \*Note: This test does not take into account the repeated measures for each participant and the organic treatment duration. The results of the linear-mixed effect models are the ones considered (reported in a section below) as they take into account the repeated measures for each participant and the organic treatment duration.
Time frame: 1 baseline sample, 2 samples in the conventional period (typical conventional diet) and 3 samples in the organic period, up to 40 days for each Period
Population: Three schools were randomly allocated to Group 1 (67 children) and the other three to Group 2 (124 children). In total, 24 children from Group 1 and 18 children from Group 2 who withdrew from the study 1-11 days after the beginning of the organic period and did not provide an organic period urine sample, were excluded from the data analysis.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| % Change in 3-PBA Between Last Sample of Conventional Period and Last Sample of Organic Period | Overall Difference in Median MDA Levels in Urine Between the Conventional and Organic Periods* | 858 umol/g creatinine |
| Median 3-PBA Levels in the Organic Period | Overall Difference in Median MDA Levels in Urine Between the Conventional and Organic Periods* | 846 umol/g creatinine |
Comparison: The overall differences in the medians of biomarkers between the conventional and the organic periods were assessed with the non-parametric Wilcoxon rank sum testp-value: 0.338Wilcoxon rank sum test