BackgroundThe association between daily protein intake and osteoporosis is still controversial and only a few studies have explored the issue in Korea. This study investigated the relationship between daily protein intake and the prevalence of osteoporosis in Korean adults.MethodsThis study analyzed data extracted from the Korean National Health and Nutrition Examination Survey 4. Participants were aged 19 years or older and had never been treated for osteoporosis. The percentage of calories coming from protein intake was assessed by 24-hour recall method, and participants were divided into three groups according to recommended daily dietary protein intake as a proportion of total daily calories (i.e., <10%, 10%-20%, and >20%). A lumbar or femur neck bone mineral density T-score less than -2.5 was indicative of the presence osteoporosis. The influence of daily protein intake on the prevalence of osteoporosis was analyzed.ResultsIn both sexes, the group with the highest protein intake had significantly lower odds of developing lumber osteoporosis when compared to the group with the lowest protein intake, after adjusting for associated factors (females: odds ratio [OR], 0.618; 95% confidence interval [CI], 0.610 to 0.626; P for trend <0.001; males: OR, 0.695; 95% CI, 0.685 to 0.705; P for trend <0.001).ConclusionSufficient daily protein intake lowered the prevalence of osteoporosis in Korean adults. Further prospective studies are necessary to verify the preventive effect of adequate protein intake on osteoporosis.