CONCLUSIONS Dietary calcium intake is not associated with risk of fracture , and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures .
OBJECTIVE To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures .
Exercise and Other Factors in the Prevention of Hip Fracture: The Leisure World Study
As part of a prospect i ve study begun in 1981 , we evaluated 8,600 postmenopausal women and 5,049 men residing in a southern California retirement community for risk factors for hip fracture . Incidence rates were twice as high in women as in men , but in both sexes the rates nearly doubled every 5 years between 70 and 90 years . Active exercise was strongly and negatively associated with hip fracture risk in both sexes ; the age-adjusted relative risk was 0.6 and 0.5 for females and males , respectively , for 1 or more hours of exercise per day compared with less than 1/2 hour of exercise . A high body mass index ( upper tertile of weight divided by height squared ) was associated with a strong reduction in hip fracture risk for females ( RR = 0.5 ) . Current cigarette smokers had a significantly increased risk ( RR = 1.8 and RR = 2.2 for females and males , respectively ) compared with never-smokers , but the risk for past smokers was not different from that of lifetime nonsmokers . Other factors related to reduced hip fracture risk in women were high parity , late age at menarche , and long menstrual cycle length . These age-adjusted relative risk estimates did not change material ly in multivariate analysis when adjusted simultaneously for age , active exercise , body mass , smoking , and , for women , age at menarche and number of children . Among estrogen users , the lowest risk of hip fracture was observed for recent users ( RR = 0.8 ) , while users who had stopped estrogen use 15 or more years ago had a relative risk of 1.1 , suggesting that the protective effect of estrogen dissipates after many years since cessation of estrogen
CONCLUSIONS Dietary calcium intake is not associated with risk of fracture , and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures .
OBJECTIVE To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures .