Sex ratios in the Arctic--do man-made chemicals matter?

Centre for Health Research in Greenland, National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
American Journal of Human Biology (Impact Factor: 1.7). 03/2012; 24(2):165-9. DOI: 10.1002/ajhb.22214
Source: PubMed

ABSTRACT The objective was to analyze the variation of secondary sex ratios across the Arctic and to estimate the time trend. The rationale for this was claims in news media that, in the Arctic, sex ratios have become reduced due to exposure to anthropogenic contaminants in the environment.
Data was collected from 27 circumpolar jurisdictions from public websites of the eight Arctic countries. Sex ratios at birth were calculated for each jurisdiction and each available year. Linear regression models of the sex ratios across time were fit within each jurisdiction to estimate the change in sex ratio over time.
All male:female sex ratios were close to 1.05 with time trends close to 0. In a Bayesian hierarchical model overall sex ratio was estimated at 1.054 (95% confidence interval 1.048, 1.058). The estimate for the 10-year slope across all jurisdictions was 0.0010 (95% confidence interval -0.0021, 0.0046). Separate analyses of indigenous populations in Alaska and Greenland gave similar results and similar sex ratios were found among Greenland Inuit in 1900 and today.
The absence of deviation of the secondary sex ratio in any of the Arctic jurisdictions indicates that the contaminants that are present are not disrupting endocrine systems to the extent that sex ratios are being affected.

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Available from: Kue Young, Sep 29, 2015
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    • "Interestingly, the study reported little variation in an SSR of 1.05 over time and between regions despite considerable climatic variation. In fact, the SSR of present day indigenous Greenland Inuits is 1.043 compared to 1.048 from 1901–1930 (Bjerregaard et al. 2012). Thus, while extreme cold temperatures in the Arctic affect infant survival (Young and Mäkinen 2010), whether or not fluctuations in temperature influence the SSR remains to be determined. "
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