Long-term dietary vitamin D intake and risk of fracture and osteoporosis : a longitudinal cohort study of Swedish middle-aged and elderly women

• Context: Vitamin D deficiency may lead to osteoporosis and fracture but the importance of dietary vitamin D intake for skeletal health in adults is uncertain.Objective: To investigate associations between long-term dietary intake of vitamin D with risk of fractures and osteoporosis.Design: A prospective longitudinal cohort study.Setting: The population-based Swedish Mammography Cohort and the subcohort SMC Clinical.Participants: 61,433 women (age range 38 to 76 years) were followed for 19 years. Of these, 5,022 participated in the subcohort. Diet was assessed by repeated food frequency questionnaires.   Main outcome measures: Incident fractures of any type and hip fractures, which were identified from registry data. Secondary outcome was osteoporosis diagnosed by dual energy x ray absorptiometry in the subcohort.Results: 14,738 women experienced any type of first fracture during follow-up, with 3,871 of these being hip fractures. Twenty percent of the women in the subcohort were classified as osteoporotic. A multivariable-adjusted hazard ratio (HR) and 95% confidence interval (CI) for any first fracture was 0.96 (95% CI 0.92-1.01) for the lowest and 1.02 (95% CI 0.96-1.07) for the highest quintile when compared with the third quintile of vitamin D intake. The corresponding HR for a first hip fracture was 1.02 (95% CI, 0.96-1.08) for the lowest and 1.14 (95% CI, 1.03-1.26) for the highest quintile. The odds ratio of osteoporosis by quintiles of vitamin D intake was 1.20 (95% CI, 0.85-1.71) for the lowest and 0.99 (95% CI, 0.78-1.25) for the highest quintile. Bone mineral density, however, were 2% higher at the lumbar spine and 0.3% higher at the total hip in women with highest vs. women with lowest intake of vitamin D (p<0.0001). Conclusions: Dietary intake of vitamin D seems to be of minor importance for the occurrence of fractures and osteoporosis in community-dwelling Swedish middle-aged and elderly women.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Ortopedi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Orthopaedics (hsv//eng)

Nyckelord

Vitamin D

fraktur

BMD

observationsstudie

Epidemiologi

Epidemiology

Orthopaedics

Ortopedi

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