Relationships between SF-36 health profile and bone mineral density: the Hertfordshire Cohort Study

Abstract

We utilised the Hertfordshire Cohort Study (HCS) to relate bone mineral density (BMD) to SF-36 health-related quality of life scores. We studied 737 men and 675 women who had completed a home interview and clinic. Four hundred and ninety-eight men and 468 women subsequently attended for bone densitometry [dual-energy X-ray absorptiometry (DXA)]. SF-36 questionnaire responses were mapped to eight domains: physical function (PF), role physical (RP), role emotional (RE), social functioning (SF), mental health (MH), vitality (VT), bodily pain (BP) and general health perception (GH). Subjects with scores in the lowest gender-specific fifth of the distribution were classified as having "poor" status for each domain. Odds ratios (OR) for poor status for each domain were calculated per unit increase in lumbar spine or total femoral BMD t score. Among men after adjustment for age, BMI, social class, lifestyle (including physical activity) and known comorbidity, higher total femoral t score was associated with decreased prevalence of poor SF-36 scores for PF [OR 0.72 (95%CI 0.53, 0.97), p=0.03], SF [OR 0.70 (95%CI 0.53, 0.94), p=0.02] or GH domains [OR 0.74 (95%CI 0.56, 0.99), p=0.05], but no relationships were apparent between SF-36 scores and lumbar spine t score. Among women, the adjusted relationship between higher total femoral t score and decreased prevalence of poor PF was consistent [OR 0.71 (95%CI 0.50, 1.00), p=0.05], but no other relationships were significant. Poorer functioning (assessed by SF-36 questionnaire) is associated with lower total femoral BMD in older men (but less so in women) after adjustment for lifestyle factors and comorbidity.