PCBs, other pollutants delay pregnancy?

Given much higher exposures during the mid-20th century, would there have been baby-boomers or Gen-Xers if this were true? [NIH News]


  1. Interesting. No data on how long the couples had been sexually active, number of partners, previous birth control methods, etc. Guess chemicals overcome all of those? Plus, DDE was included, even though banning DDT took care of that here and there was no information on how the exposure occurred. If the participants were from other countries, that maybe might have had some effect on the study’s results. Maybe?

  2. One real, proven and heavy-hitting factor in human fertility is civilisation. More specifically, career choices people make (degrees, promotions and other irrelevant stuff that takes precedence over having children). And there are thousads of other detrimental factors that are associated with civilisation, mostly having to do with human behaviour, and very little with PCBs and other molecules that co-occur with civilisation in big cities, where populations congregate to die, rather than proliferate. Virtually everything you find in an urban environment can be statistically associated with low fertility.

  3. Goodness, junkscience seekers will find lots to address in this study, including the use of odds ratios for associations that could be nothing more than random chance findings (tiny correlations of 4 to 32%); numerous confounding factors that don’t appear to have been factored for, such as socioeconomic status, careers, stress, dieting; the high drop-out rates; and associations not reported as dose related. Like all data dredges, oftentimes the associations make no sense and fail to support the author’s conclusions. For example, they found pcb 101 was associated with a 28% greater fertility in men.

    In the study they write: “The etiologic mechanisms … remain elucive.” and “Delineating an underlying causal model that might explain the correlations…remains a critical data gap.”

    Even so, note in the NIH press release that they were quick to advice couples to reduce their exposure by eating less fatty meat and fish and animal products.

    The NIH press release said “the investigators noted that they cannot rule out that some of the delays they observed may have been due to exposure to multiple chemicals.” How about because of random chance?


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