Relationship between major dietary patterns and osteoporosis in Iranian postmenopausal women: A case-control study

Osteoporosis is a common skeletal disorder in the elderly characterized by a bone density lower than 2.5 standard deviations in young adults. Diet may play an important role in the pathogenesis of osteoporosis. The aim of this study was to determine the possible relationship between major dietary patterns and osteoporosis in Iranian postmenopausal women. A case-control study was conducted on 440 postmenopausal women in Tehran using convenient sampling that included 220 cases and 220 controls. Demographic and anthropometric data, medical history, physical activity and usual dietary intake were collected through interviews. A 147-item Food Frequency Questionnaire was used to assess dietary patterns. The levels of physical activity and nutrient intake between the two groups were compared. The principal component analysis (PCA) was used to determine dominant dietary patterns. Two dominant dietary patterns (mixed and western) patterns were identified using 33 food groups. There was a significant difference in nutritional status and physical activity between the case and control groups. After adjusting for the effect of possible confounding variables (Model 4), those in the second tertile of the Western dietary pattern were significantly more likely to have osteoporosis than in the first tertile (OR=3.87/95% CI=1.13-7.03). The western dietary pattern was strongly associated with an increased risk of osteoporosis. In addition, no association was found between mixed dietary patterns and osteoporosis.