A descriptive analysis of first trimester urinary concentrations of 14 bisphenol analogues in the MIREC Canadian pregnancy cohort

BACKGROUND

Concern over the health effects of BPA, particularly for the developing fetus, has led to an increasing use of bisphenol analogues in industrial and consumer products, which may be as hormonally active as BPA. Biomonitoring data for many bisphenol analogues, especially in pregnant populations, are limited.

METHODS

We measured concentrations of 14 bisphenol analogues in 1st trimester urine samples (n = 1851) from the Maternal-Infant Research on Environmental Chemicals (MIREC) Canadian pregnancy cohort (2008-2011). We examined patterns of exposure according to sociodemographic and sampling characteristics as well as occupation and frequency of consumption of canned fish within the previous 3 months.

RESULTS

BPA was detected in 89% of participants with a specific gravity standardized geometric mean concentration of 0.990 μg/L. Biphenol 4,4' (BP 4,4'), 4,4'-dihydroxydiphenyl ether (DHDPE), and bisphenol E (BPE) were detected in >97% of participants. Bisphenol F (BPF) and bisphenol S (BPS) were detected in >60% of participants. Specific gravity standardized geometric mean concentrations of these 5 compounds ranged from 0.024 to 0.564 μg/L. Nine bisphenol analogues were detected in <9% of participants. Concentrations of BP 4,4', DHDPE, and BPE were higher in younger women and those with higher pre-pregnancy BMI, lower household income, lower education, and among smokers. We found a similar pattern of differences in BPF for age, education, and smoking status while BPS similarly differed across categories of pre-pregnancy BMI. Participants who were unemployed or working in the service industry had higher molar sum of 7 bisphenol analogues than those working in healthcare, education, or an office setting. Canned fish consumption was not related to bisphenol analogue concentrations.

CONCLUSION

BP 4,4', DHDPE, BPE, BPF, and BPS were highly detected in 1st trimester urine samples in this large pan-Canadian pregnancy cohort. This suggests widespread exposure to these analogues around 2008-2011 and warrants further investigation into associations with health outcomes.

Imputing accelerometer nonwear time in children influences estimates of sedentary time and its associations with cardiometabolic risk

Background

A limitation of measuring sedentary time with an accelerometer is device removal. The resulting nonwear time is typically deleted from the data prior to calculating sedentary time. This could impact estimates of sedentary time and its associations with health indicators. We evaluated whether using multiple imputation to replace nonwear accelerometer epochs influences such estimates in children.

Methods

452 children (50% male) aged 10–13 were tasked with wearing an accelerometer (15 s epochs) for 7 days. On average, 8% of waking time was classified as nonwear time. Sedentary time was derived from a “nonimputed” dataset using the typical approach of deleting epochs that occurred during nonwear time, as well as from an “imputed” dataset. In the imputed dataset, each nonwear epoch was re-classified as being as sedentary or not using multiple imputation (5 iterations) which was informed by the likelihood of a wear time epoch being classified as sedentary or not using parameter estimates from a logistic regression model. Estimates of sedentary time and associations between sedentary time and health indicators (cardiometabolic risk factor and internalizing mental health symptoms Z-scores) were compared between the nonimputed and imputed datasets.

Results

On average, sedentary time was 33 min/day higher in the imputed dataset than in the nonimputed dataset (632 vs. 599 min/day). The association between sedentary time and the cardiometabolic risk factor Z-score was stronger in the imputed vs. the nonimputed dataset (β = 0.137 vs. β = 0.092 per 60 min/day change, respectively). These findings were more pronounced among children who had < 7 days with ≥10 h of wear time.

Conclusion

Researchers should consider using multiple imputation to address accelerometer nonwear time, rather than deleting it, in order to derive more unbiased estimates of sedentary time and its associations with health indicators.

Associations between weight-related teasing and psychosomatic symptoms by weight status among school-aged youth

Objective

Weight‐related teasing (WT) is associated with poor mental health. This study examined whether weight status moderates the relationship between WT and psychosomatic symptoms within a representative sample of school‐aged youth.

Methods

Data are from the Canadian 2013/2014 Health Behaviour in School‐aged Children Survey, a nationally representative sample of youth in Grades 6–10. WT, psychosomatic symptoms and body mass index (BMI) were self‐reported.

Results

The final sample consisted of 20,277 youth (mean age = 14.2 years; 50.2% female). The prevalence who reported being WT at least once a week was 4.6%, 8.1% and 17.3% among youth with normal weight, overweight, and obesity, respectively (p < 0.001). There was a gradient relationship between the frequency of WT and psychosomatic symptoms (p < 0.001). By comparison to youth that were not WT, psychosomatic symptom z‐scores were significantly (p < 0.05) higher in youth that were WT one to two times in the past few months (0.47, 95% CI: 0.41–0.53), two to three times per month (0.65, 0.52–0.77), about once a week (0.82, 0.71–0.93) and several times a week (0.98, 0.84–1.12). However, the WT * BMI category interaction term was not significant (p = 0.86).

Conclusions

Victims of WT experienced more psychosomatic symptoms independent of BMI category; however, BMI category did not moderate the association between WT and psychosomatic symptoms.

Comparison of ActiGraph GT3X+ and Actical accelerometer data in 9-11-year-old Canadian children

Accelerometry is the gold standard for field-based physical activity assessment in children; however, the plethora of devices, data reduction procedures, and cut-points available limits comparability between studies. This study aimed to compare physical activity variables from the ActiGraph GT3X+ and Actical accelerometers in children under free-living conditions. A cross-sectional study of 379 children aged 9-11 years from Ottawa (Canada) was conducted. Children wore the ActiGraph GT3X+ and Actical accelerometers on the hip simultaneously for 7 consecutive days (24-h protocol). Moderate-to-vigorous (MVPA), vigorous (VPA), moderate (MPA), and light (LPA) physical activity, as well as sedentary time, (SED) were derived using established data reduction protocols. Excellent agreement between devices was observed for MVPA (ICC = 0.73-0.80), with fair to good agreement for MPA, LPA and SED, and poor agreement for VPA. Bland-Altman plots showed excellent agreement for MVPA, LPA, and SED, adequate agreement for MPA, and poor agreement for VPA. MVPA derived from the Actical was 11.7% lower than the ActiGraph GT3X+. The ActiGraph GT3X+ and Actical are comparable for measuring children's MVPA. However, comparison between devices for VPA, MPA, LPA, and SED are highly dependent on data reduction procedures and cut-points, and should be interpreted with caution.