Dietary calcium and vitamin K are associated with osteoporotic fracture risk in middle-aged and elderly Japanese women, but not men: the Murakami Cohort Study.

Although dietary Ca, vitamin D and vitamin K are nutritional factors associated with osteoporosis, little is known about their effects on incident osteoporotic fractures in East Asian populations. This study aimed to determine whether intakes of these nutrients predict incident osteoporotic fractures. We adopted a cohort study design with a 5-year follow-up. Subjects were 12 794 community-dwelling individuals (6301 men and 6493 women) aged 40-74 years. Dietary intakes of Ca, vitamin D and vitamin K were assessed with a validated FFQ. Covariates were demographic and lifestyle factors. All incident cases of major osteoporotic limb fractures, including those of the distal forearm, neck of humerus, neck or trochanter of femur and lumbar or thoracic spine were collected. Hazard ratios (HR) for energy-adjusted Ca, vitamin D and vitamin K were calculated with the residual method. Mean age was 58·8 (sd 9·3) years. Lower energy-adjusted intakes of Ca and vitamin K in women were associated with higher adjusted HR of total fractures (Pfor trend = 0·005 and 0·08, respectively). When vertebral fracture was the outcome, Pfor trend values for Ca and vitamin K were 0·03 and 0·006, respectively, and HR of the lowest and highest (reference) intake groups were 2·03 (95 % CI 1·08, 3·82) and 2·26 (95 % CI 1·19, 4·26), respectively. In men, there were null associations between incident fractures and each of the three nutrient intakes. Lower intakes of dietary Ca and vitamin K were independent lifestyle-related risk factors for osteoporotic fracture in women but not men. These associations were robust for vertebral fractures, but not for limb fractures.

Total physical activity and risk of chronic low back and knee pain in middle-aged and elderly Japanese people: The Murakami cohort study.

BACKGROUND: Specific components of physical activity, such as vigorous exercise and heavy occupational work, are known to increase the risk of chronic low back pain (CLBP) and chronic knee pain (CKP), but impacts of other components are less known. This study aimed to assess the relationship between total physical activity and risk of CLBP and CKP from a public health perspective. METHODS: Participants were 7,565 individuals, aged 40-74 years, who did not have CLBP or CKP, and who participated in the 5-year follow-up survey. A self-administered questionnaire was used to obtain information on demographics, body size and lifestyle (including physical activity) in the baseline survey in 2011-2013, and on CLBP and CKP using Short Form 36 (SF-36) in the follow-up survey. Sitting, standing, walking and strenuous work for occupational activity were assessed for total physical activity, and walking slowly, walking quickly, light to moderate exercise and strenuous exercise were assessed for leisure-time physical activity using metabolic equivalent hours/day (METs score). RESULTS: Mean age of participants was 60.1 years (SD, 8.8). Participants with higher METs scores had a significantly higher risk of CKP (p for trend = 0.0089, OR of 4th quartile = 1.29, 95% CI: 1.04-1.59 vs. 1st quartile), but not CLBP. An intermediate leisure-time METs score was associated with a lower risk of CLBP (OR = 0.75, 95%CI: 0.61-0.92 vs. 0 METs-group). CONCLUSIONS: A high level of total physical activity may increase the risk of CKP, whereas an intermediate level of leisure-time physical activity may decrease the risk of CLBP, in middle-aged and elderly individuals. SIGNIFICANCE: Evidence on the longitudinal association between total physical activity and CLBP and CKP in middle-aged and elderly people is lacking. We conducted a cohort study to assess this association, and found that high levels of total physical activity increased risk of CKP, and intermediate levels of leisure-time physical activity decreased risk of CLBP. This suggests that the effect of physical activity on chronic pain differed by pain site.