Long-term mental distress, bone mineral density and non-vertebral fractures. The Tromsø Study

The purpose of this study was to examine, prospectively, the risk of non-vertebral fractures and low bone mineral density in a population-based cohort with respect to indicators of subjective mental distress. In 1979-1980 all males born 1925-1959 and all females born 1930-1959 living in Tromsø were invited (21,441; response rate, 78%). The same individuals were invited to the subsequent studies in 1986-1987 and 1994-1995 (74% attended the first two, and 71% attended all three surveys). Non-vertebral fractures were registered by linkage to the hospital X-ray register for the period 1988-1995, and forearm bone mineral density (BMD) was available in a subsample of 4,690 who had attended three times. Questions about mental distress (depression, insomnia and coping problems) were repeated three times and analyzed as cumulated exposure. Women who reported being depressed at two time points had an adjusted odds ratio (OR) =2.5 (95% confidence interval [CI] 1.3-4.9) for sustaining a non-vertebral fracture and OR=3.1 (95% CI 1.3-7.2) for sustaining an osteoporotic fracture, compared with those without depression on any occasion. The corresponding odds ratios for those with coping problems at two time points were slightly higher, whereas sleeping problems seem only to be weakly associated with non-vertebral fractures. The pattern of associations and the magnitude of OR estimates were mainly the same in women younger than 50 years and those 50 years and older. Women using nerve medicine and reporting depression twice had an odds ratio of 4.4 (95% CI 1.1-17.7) for sustaining a non-vertebral fracture, and those using nerve medicine and reporting coping problems twice had a corresponding OR 4.7 (95% CI 1.2-18.4). Among men no significant associations were found for either fracture type. No association was found between mean BMD and number of times reporting depression, insomnia or coping problems, in women or men. Long-term mental distress is associated with risk of all non-vertebral fractures and osteoporotic fractures in middle-aged women, but not in men. Mental distress itself seems to be more important than the use of nerve medicine.