Social disadvantage, bone mineral density and vertebral wedge deformities in the Tasmanian Older Adult Cohort

Summary: The relationship between social disadvantage and bone mineral density (BMD) is complex and remains unclear; furthermore, little is known of the relationship with vertebral deformities. We observed social disadvantage to be associated with BMD for females, independent of body mass index (BMI). A lower prevalence of vertebral deformities was observed for disadvantaged males.

Introduction: The relationship between social disadvantage and BMD appears complex and remains unclear, and little is known about the association between social disadvantage and vertebral wedge deformities. We examined the relationship between social disadvantage, BMD and wedge deformities in older adults from the Tasmanian Older Adult Cohort.

Methods: BMD and wedge deformities were measured by dual-energy X-ray absorptiometry and associations with extreme social disadvantage was examined in 1,074 randomly recruited population-based adults (51 % female). Socioeconomic status was assessed by Socio-economic Indexes for Areas values derived from residential addresses using Australian Bureau of Statistics 2001 census data. Lifestyle variables were collected by self-report. Regression models were adjusted for age, BMI, dietary calcium, serum vitamin D (25(OH)D), smoking, alcohol, physical inactivity, calcium/vitamin D supplements, glucocorticoids and hormone therapy (females only).

Results: Compared with other males, socially disadvantaged males were older (65.9 years versus 61.9 years, p = 0.008) and consumed lower dietary calcium and alcohol (both p ≤ 0.03). Socially disadvantaged females had greater BMI (29.9 ± 5.9 versus 27.6 ± 5.3, p = 0.002) and consumed less alcohol (p = 0.003) compared with other females. Socially disadvantaged males had fewer wedge deformities compared with other males (33.3 % versus 45.4 %, p = 0.05). After adjustment, social disadvantage was negatively associated with hip BMD for females (p = 0.02), but not for males (p = 0.70), and showed a trend for fewer wedge deformities for males (p = 0.06) but no association for females (p = 0.85).

Conclusions: Social disadvantage appears to be associated with BMD for females, independent of BMI and other osteoporosis risk factors. A lower prevalence of vertebral deformities was observed for males of extreme social disadvantage. Further research is required to elucidate potential mechanisms for these associations.