Cigarette smoking, alcohol and caffeine consumption, and bone mineral density in postmenopausal women

The aim of this analysis was to compare the effects of different measures o f cigarette, alcohol and caffeine consumption upon bone mineral density (BM D). Five hundred and eighty postmenopausal women aged 45-59 years at recrui tment completed a risk factor questionnaire that contained detailed section s on cigarette, alcohol and caffeine consumption. BMD was measured using du al-energy X-ray absorptiometry. Measurements taken at five bone sites were used: anterior-posterior spine, femoral neck, greater trochanter, radius/ul na and whole body. The data were analyzed using multiple linear regression, adjusting for a number of established BMD risk factors. BMD was more stron gly related to the number of months spent smoking than to pack-years of smo king at all five sites (p <0.05 at four of the five sites). There were sign ificant reductions in BMD when comparing smokers with non-smokers at ages 2 0, 30 and 40 years, but not for current smoking. Lifetime alcohol consumpti on and current alcohol consumption did not have an independent association with BMD. However, the heaviest beer drinkers in the sample had a particula rly low bone density. Caffeine consumption at various ages was not associat ed with BMD. The results of these analyses suggest that for predicting BMD a simple history of smoking duration is as good as trying to obtain more de tailed smoking information, but that only 25% of the variation in BMD is ex plained by personal characteristics, family history and lifestyle factors.