Ethnic and Gender-specific Incidence Rates for Hip Fractures in South Africa: A Multi-centre Study

Background: Limited data exist on the incidence of hip fractures in South Africa (SA). We report gender and ethnic specific incidence rates of hip fractures in SA.

Methods: In a multicentre prospective study, conducted in geographically defined municipalities of three provinces in SA, a structured questionnaire was administered to all subjects aged 40 years and over, presenting with a new atraumatic hip fracture, from 1 April 2017 to 31 March 2018. Gender and ethnic specific incidence rates (IR) of hip fractures were calculated using population statistics from Statistics SA.

Findings: Of the 2767 subjects enrolled, 1914 (69·2%) were women and 853 (30·8%) were men. The majority of subjects were from the White population (40·9%) followed by those from the African (26·4%), Coloured (18·7%) and Indian (13·9%) populations. Men with hip fractures were significantly younger than women in the total group (69 [IQR 59-79] versus 77 years [IQR 68-84], p < 0·001) and in each ethnic group. White subjects were significantly older (p < 0·0001) and Africans significantly younger (p < 0·0001) than the other ethnic groups. In women, the highest IR was noted in the White population (176·0 per 100,000), followed by that in the Indian (147·7 per 100,000), Coloured (73·2 per 100,000) and African populations (43·6 per 100,000). A similar pattern was seen in men albeit at lower rates, with the highest rate in White men at 76·5 per 100,000. In the total study population and the African population, the IR was higher in men compared to women in subjects under 60 years. In the White population, the IR was higher in men compared to women in the 40-44 years age group. While in the Coloured and Indian populations the IR was higher in men compared to women in the 40-49 years and 45-54 years age groups, respectively. There was an increase in the relative risk ratios with age in the total study population, and in all ethnic groups in both women and men.

Interpretation: Hip fractures occur in all ethnic groups in South Africa with higher IRs in the White and Indian populations compared to the Coloured and African populations. Consistent with the published literature, the overall hip fracture IR was higher in women than in men, except in the younger age groups, and increased with age.

Funding: South African Medical Research Council and the University of KwaZulu-Natal Competitive Research Grant.