Methods: Medline, Embase, and CINAHL databases were searched from inception to 28th April 2021 for studies reporting an association between SES and fragility fracture risk among individuals aged ≥50 years. Risk ratios (RR) were combined in meta-analyses using random restricted maximum likelihood models, for individual-based (education, income, occupation, cohabitation) and area-based (Index of Multiple Deprivation, area-income) SES measures.
Results: A total of 61 studies from 26 different countries including more than 19 million individuals were included. Individual-based low SES was associated with an increased risk of fragility fracture (RR 1.27 [95%CI 1.12, 1.44]), whilst no clear association was seen when area-based measures were used (RR 1.08 [0.91, 1.30]). The strength of associations was influenced by the type and number of covariates included in statistical models; RR 2.69 [1.60, 4.53] for individual-based studies adjusting for age, sex and BMI, compared with RR 1.06 [0.92, 1.22] when also adjusted for health behaviours (smoking, alcohol and physical activity). Overall, the quality of the evidence was moderate.
Conclusion: Our results show that low SES, measured at the individual level, is a risk factor for fragility fracture. Low BMI and unhealthy behaviours are important mediators of the effect of SES on fracture risk. Strategies to prevent fractures and reduce unhealthy behaviours should aim to tackle structural inequalities in society thereby reducing health inequalities in fragility fracture incidence.
Bibliographical noteFunding Information:
AB was supported by a Linda Edwards Memorial PhD Studentship funded by the Royal (formerly National) Osteoporosis Society.
© 2021, International Osteoporosis Foundation and National Osteoporosis Foundation.
- health inequality
- systematic review
- socio-economic status