Perinatal Factors, Female Breast Cancer, and Associated Risk Factors in Puerto Rico: Evidence from the Atabey Epidemiology of Breast Cancer Study.

There is increasing evidence that exposures in utero and in infancy impact breast cancer risk. No previous studies have evaluated these associations among women in Puerto Rico. In a population-based case–control study of breast cancer epidemiology in the San Juan metropolitan area in Puerto Rico, we examined the association of early life factors with breast cancer risk and breast cancer risk factors. Both cases (n = 315) and controls (n = 348) completed interviewer-administered questionnaires, including self-reported birth country, birthweight, and history of having been breastfed. Comparisons of characteristics of those with and without the early life factors were made with t-tests or chi-squared tests; associations between early life factors and breast cancer risk were estimated with unconditional logistic regression adjusting for age, education, body mass index (BMI), age at menarche, parity, and menopausal status. Women who had been breastfed tended to have higher adult body mass index (BMI), higher education, and lower parity (p < 0.05). Higher birthweight was associated with higher adult BMI and lower educational attainment (p < 0.05). Those born outside of Puerto Rico or the US were more likely to have higher educational attainment and earlier age at menarche than those born within Puerto Rico or the US (p < 0.05). We found no significant associations between any of the early life factors and breast cancer risk. We did not find evidence of an association of early life factors with breast cancer risk among women in Puerto Rico.