Answered You can hire a professional tutor to get the answer.
Katerine Perez 101032911 Summary In "Global warming the greatest scam in history claims founder of Weather Channel", Jason Taylor states that the...
Table options
Discussion and limitations
This study provided the first Canadian data on personal care product use and urinary maternal TCS concentrations throughout pregnancy. It indicated that pregnant women were exposed to TCS through product sources such as oral care products and hand soaps/sanitizers; the detection of maternal urinary TCS concentrations persisted throughout the duration of the pregnancy as well as postpartum.
Our study findings showed that products containing TCS were primarily “oral care products” and “hand soaps/sanitizers”. Meeker et al. (2013) reported that liquid soap and hair spray use were associated with higher urinary TCS concentrations and Koch and colleagues (2014) reported that urinary concentrations were substantially higher in urine of adults using toothpaste with TCS. Uses of antibacterial soaps in healthcare settings and TCS-containing toothpaste have also been shown to increase urinary TCS concentrations in healthcare workers (MacIsaac et al., 2014); however a Swedish study of mothers reported no obvious differences in TCS levels between users and nonusers of products which may contain TCS, although only 37% of the urine samples were above the detection limit (Larsson et al., 2014). Estimating a quantitative dose of TCS based on the specific product would provide additional information with respect to primary sources of exposure to TCS and would be an important future research direction.
The unadjusted geometric mean maternal urinary TCS concentration reported in this study (21.6 μg/L) was higher than several previously reported studies of pregnant women in Canada (Arbuckle et al., 2015a; 12.64 μg/L), Boston (LaRocca et al., 2014; 13.8 μg/L), the US NHANES (Woodruff et al., 2011; 17.0 μg/L), Norway (Bertelsen et al., 2014; <2.3 μg/L), and Denmark (Frederiksen et al., 2014; 1.21 μg/L). Our maternal TCS concentrations were comparable to those of pregnant women in California (California, 2013; 17.2 μg/L), multiple US sites (Mortensen et al., 2014; 19.0 μg/L) and in Canadian women of reproductive age (Health Canada, 2013; 19.0 μg/L) or in the case of a study in Puerto Rico, lower (Meeker et al., 2013; 29.9 μg/L). A number of factors such as number of collections, socio-economic status and availability of triclosan-containing products may account for these differences. The overall intraclass correlation coefficient of 0.50 indicated moderate reproducibility among urine samples collected across pregnancy. This result was comparable to that of recent studies (Meeker et al., 2013, Philippat et al., 2013 and Bertelsen et al., 2014), who reported adjusted intraclass coefficients between 0.47 and 0.58, based on several spot samples collected over the pregnancy. The intraclass correlation coefficients of the P4 study 24-h unadjusted serial urine samples were 0.78 for week-day samples and 0.79 for week-end day samples, both indicating high reproducibility for samples collected within a day. In a Belgian adult population where all urine voids were collected over 6 days, the ICC for spot samples was 0.93 (Koch et al., 2014). This result is not surprising given the correlation between product uses and urinary TCS levels and assuming that the same products are used on consecutive days. In agreement with Bertelsen et al. (2014), our results suggest that given the costs and participant burden of collecting serial urine samples, a single spot urine sample can moderately represent a person's exposure over the pregnancy and can be especially relevant for women with high exposure.
The surrogate category analysis indicated that the predictive ability of a single spot urine sample was lower when identifying individuals with moderate urinary metabolite concentrations, as compared to high concentrations. A recent Health Canada publication (Saner, 2010) emphasized the importance of exposure in risk assessments, as a higher exposure may increase the chances of an adverse health effect; however, in the specific case of endocrine disrupting chemicals, health effects can occur at lower levels of exposure that would not have been predicted based on exposures at higher levels (Vandenberg et al., 2012). In this study, single spot urine samples correctly predicted high metabolite concentrations (GM > 78.12 μg/L) more than 90% of the time, and correctly predicted low metabolite concentrations (GM < 11.77 μg/L) between 86% and 96% of the time.
Univariate models controlling for specific gravity were previously reported (Arbuckle et al., 2015b). Similar results were observed in the multivariate model of this study. SG-adjusted urinary TCS concentrations were lowest between 16:00 and 23:59. As the urinary half-life of TCS is approximately 11 h (Sandborgh-Englund et al., 2006), the low concentrations at this time are likely a reflection of a low number of TCS product uses in the early morning hours.
In our study, women with household incomes between $80,000 and 100,000 had significantly lower TCS exposure than women with incomes greater than $100,000. This result agrees with a larger study of Canadian pregnant women which reported a positive association between household income and urinary TCS levels (Arbuckle et al., 2015a). Similarly, both studies concluded that women with no previous pregnancies had the highest urinary GM TCS.
Similar to other studies (Woodruff et al., 2011, Meeker et al., 2013 and Philippat et al., 2013), our sample was highly educated. It is unknown how this may have influenced their exposure to TCS; however, it does limit the generalizability of the study results to other socio-demographic strata. A larger sample size would have increased the precision and power of the results; and may have resulted in finding associations between urinary TCS and age and education, as previous studies have reported (Wolff et al., 2008, Ye et al., 2008 and Kim et al., 2011).
An important limitation of the study is self-selection bias occurring among the participants. This may have been reflected by women who reported using TCS-containing products providing far more urine samples than those who did not report using any TCS-containing products.
Another limitation of the study is that approximately 25% of all self-reported product uses had insufficient information to properly identify whether or not TCS was an active ingredient in the product. It is possible that the actual number of TCS products used may be greater than 4.41%. Although efforts were made to make the completion of the “Product Use Booklets” and “Food and Activity Diaries” as user-friendly as possible, it is anticipated that missing data (and therefore under-reporting of products) are a concern. Among the women reporting to not have been exposed to TCS, they still had detectable levels of TCS in their urine samples, although it was lower than those who did report exposure to TCS products. This likely also reflects the under-reporting of triclosan use.
Summary and conclusions
This study set out to address the existing knowledge gaps pertaining to urinary TCS data in Canadian pregnant women. It was the first of its kind to provide data on personal care product use and urinary maternal TCS concentrations within a day on a week-day and week-end and throughout pregnancy. It also provided critical information on the ability of a single spot urine sample collected in pregnancy to accurately predict the woman's exposure to TCS (87%). Urinary TCS concentrations tended to be consistent across pregnancy, with concentrations lowest for samples collected between 16:00 and 23:59.
A positive association was observed between the number of TCS products used and urinary TCS concentrations. However, as only about a quarter of the variance in TCS concentrations was explained by this metric, further research is needed to identify the primary sources.
As the data reflect a small subset of the Canadian population, the study results may not be generalizable to other populations; however, they provide important information towards understanding the nature of and some of the sources of exposure to TCS.
Additional studies are required to further examine the associations between specific covariates and urinary TCS concentrations and confirm the results that were found in this study.
Acknowledgements
This study would not have been possible without the participants of the P4 Study and the efforts of the OMNI Research Group. This project was funded by Health Canada's
