NEW YORK, Sep 01 (Reuters Health) -- Exposure to higher-than-average levels of maternal testosterone before birth may raise a daughter's risk for smoking in later life, according to researchers.
``Prenatal testosterone exposure is a previously unrecognized risk factor for smoking among female offspring,'' write Dr. Denise Kandel, of Columbia University in New York, and Dr. Richard Udry, of the University of North Carolina at Chapel Hill. Their findings are published in the September issue of the American Journal of Public Health.
While testosterone is commonly known as the 'male' hormone, women also produce small amounts of the hormone.
Seeking to identify prenatal influences on adult smoking behaviors, the researchers examined blood samples (taken during pregnancy) from 240 sets of parents of female offspring. Both mothers and daughters were interviewed as the daughters reached 15 to 17 years of age, and daughters were re-interviewed again as they reached 27 to 30 years of age.
The authors report that maternal blood levels of cotinine -- a 'marker' for maternal smoking -- appeared to have no association with the likelihood that a daughter would smoke in later age.
However, ``smoking among daughters during adolescence was (partially) determined by maternal prenatal testosterone,'' according to the researchers. Daughters whose mothers smoked during and after pregnancy also had higher risks for smoking in later life than daughters of non-smoking mothers.
In addition, the team note that among the daughters studied, smoking during adolescence was often associated with smoking in adulthood.
How might fetal testosterone exposure influence adult female smoking behaviors? The study authors suggest that nicotine may cause changes in the fetal brain that affect the brain's response to the chemical.
The researchers also note that ``male sex hormones affect... brain structures and functions that contribute to sex differences in behavior.'' These behaviors include ``novelty and sensation seeking'' behaviors -- including smoking.
Kandel and Udry point out that while male offspring regulate their own testosterone levels, ``in female fetuses... testosterone levels are determined by maternal levels.'' They speculate that fetal exposure to relatively high levels of testosterone could initiate a pattern of above-average testosterone levels in female children as they mature -- raising their likelihood of unhealthy behaviors like smoking.
Kandel and Udry stress that their findings are ``novel,'' and they say the exact relationship between maternal testosterone levels and daughter's smoking ``remains to be elucidated.''
SOURCE: American Journal of Public Health 1999;89:1377-1383.