Vertebral fracture prevalence and risk factors for fracture in The Gambia, West Africa: the Gambian Bone and Muscle Ageing Study

Abstract

There are limited data describing the epidemiology of vertebral fractures (VF) from resource-limited settings, where the ageing population is growing most rapidly. We aimed to determine the prevalence, incidence, and risk factors for VF in The Gambia, West Africa. The Gambian Bone and Muscle Ageing Study is a prospective observational study in men and women aged 40 years and over. Rural participants had baseline measurements and plasma samples collected and were followed up 6-8 years later; urban participants had a single measurement. DXA scans were obtained to assess areal bone mineral density (aBMD), body composition and VF. Prevalence and incidence were calculated. Risk factors for prevalent and incident fracture were tested using logistic regression, in men and women separately, with and without adjustment for age and BMI. At baseline, 581 individuals (298 women) had useable scans, 214 (127 women) at follow-up. Prevalence of VF was 14.8%. Those with VF were older (65.6(11.2) vs 61.7(12.3) years, P=.01) and had lower aBMD Z-scores. For example, in women, a 1SD increase in femoral neck Z-score resulted in a lower risk of having a prevalent VF (OR [95% CI]) 0.51 [0.38, 0.73]. In men, lumbar spine Z-scores were predictive of prevalent fracture; (0.71 [0.53, 0.97]). The incidence of VF over follow-up was 12.1%. Low BMD and grip strength were associated with the odds of having an incident VF. Given the importance of prevalent VF in predicting future VF and other fragility fractures in other populations, our findings are a major cause for concern. VF prevalence in Gambian older adults is similar to elsewhere despite fractures not being a perceived issue. Risk factors were like those identified elsewhere including age, aBMD and bone resorption. Understanding the impact of these fractures is important in a region where health of the ageing population needs to be prioritized.