New York City study: Was the frequency of the down low overreported?

The September, 2006 Annals of Internal Medicine reported that nearly 10% of heterosexual men surveyed in New York City said they also had sex with men. This study was widely reported.

Now two reports in the April 3 issue of the Annals assert that the format of the survey may have caused a dramatic overreporting of homosexual sex among heterosexual men. Here is that letter:


The article by Pathela and colleagues (1) underemphasized an apparent limitation in the data cited. Self-identified heterosexual male respondents were asked whether they had had sex with a man in the previous 12 months and then were read a definition of sex, including vaginal sex. Respondents who said “yes” were disproportionately foreign-born, had low education, and were married. They also overwhelmingly reported a single sex partner in the previous year and had a very low prevalence of risky sexual behavior. This profile suggests that many may have misunderstood the question and were reporting sex with their wives rather than “vaginal” sex with other men. Persuasive supporting evidence in the article’s Discussion section described a repeated study, as yet unpublished, 2 years later, in which asking men about sex with women before asking them about sex with men produced “a much lower self-reported prevalence of men who report sex with other men.” This marked difference in data, produced by a simple flipping of question order, deserved greater attention. Instead, the only limitation prominently reported was that random digit–dialed samples exclude households without residential telephone numbers—-a triviality in light of the effects of the question wording and question order that were much less prominently disclosed. The press release associated with the report made no mention of these effects, and subsequent press reports described the finding as far more conclusive than the relevant data suggest.

Another article in the April 3 edition provides additional caution about the earlier study. In contrast to the 9.4% reported in September, 2006, these authors estimate that just over 1% of straight-identified men have had sex with men in the past year.

The April 3 issue also allows the authors of the original study, Preeti Pathela et al, to respond to their colleagues.