Background: The Hertfordshire study suggested that age of weaning and methods of infant feeding may influence adult serum low-density lipoprotein cholesterol (LDL-C) and mortality from ischemic heart disease in men. Although breastfeeding <1 year appeared to be protective compared with formula, prolonged breastfeeding (>1 year) was associated with increased LDL-C and mortality. This study tested the effect of breastfeeding duration on lipid profile in young adults.
Materials and methods: Adult volunteers whose mothers could recall the age at which their child was weaned were recruited. We excluded patients with known dyslipidemia, dyslipidemia in a first-degree relative, obesity (body mass index [BMI] >30 kg/m(2)), pregnant or within 3 months of a previous pregnancy, subjects taking medications that may affect lipid profile, or subjects with a chronic medical condition. Nutritional questionnaires and number of weekly hours of exercise were recorded. Lipid profiles were obtained after a night fast.
Results: The three groups (no breastfeeding, breastfeeding 0-6 months, or breastfeeding >9 months) did not differ in terms of age, gender, BMI, level of education, amount of exercise, and dietary style. By stepwise background multiple regression analysis taking into account exercise, nutritional habitus, age, BMI, gender, and socioeconomic status, blood lipids were not affected by duration of breastfeeding.
Conclusions: Duration of breastfeeding does not affect lipid profiles in young adults. These findings do not support negative messages on the long-term effect of prolonged lactation generated by the Hertfordshire study.