Stopping smoking and body weight in women living in the United Kingdom.

Most studies of the effect of stopping smoking on weight in women have been cross-sectional in design and have been conducted abroad. A survey of subjects still participating in the Royal College of General Practitioners Oral Contraception Study was used to examine changes in weight among women of different smoking status and living in the United Kingdom. During roughly a 26-year period, there was a threefold increase (to 15% in 1994/1995) in the prevalence of obese (body mass index [BMI] > 30) women among the cohort. Women who stopped smoking had the largest increases in mean BMI and in the proportion of obese women at 1994/95. These results support the notion that stopping smoking leads to weight gain.