Heterogeneity of breast cancer risk within the South Asian female population in England: a population-based case–control study of first-generation migrants

Abstract

South Asian women in England have a lower breast cancer risk than their English-native counterparts, but less is known about variations in risk between distinct South Asian ethnic subgroups. We used the data from a population-based case -control study of first-generation South Asian migrants to assess risks by ethnic subgroup. In all, 240 breast cancer cases, identified through cancer registries, were individually matched on age and general practitioner to two controls. Information on the region of origin, religious and linguistic background, and on breast cancer risk factors was obtained from participants. Breast cancer odds varied significantly between the ethnic subgroups (P ¼ 0.008), with risk increasing in the following order: Bangladeshi Muslims (odds ratio (OR) 0.33, 95% confidence interval (CI): 0.10, 1.06), Punjabi Hindu (OR 0.59, 95% CI: 0.33, 1.27), Gujarati Hindu (1 ¼ reference group), Punjabi Sikh (OR 1.23, 95% CI: 0.72, 2.11) and Pakistani/Indian Muslims (OR 1.76, 95% CI: 1.10, 2.81). The statistically significant raised risk in Pakistani/Indian Muslims increased with adjustment for socioeconomic and reproductive risk factors (OR 2.12, 95% CI: 1.25, 3.58), but was attenuated, and no longer significant, with further adjustment for waist circumference and intake of nonstarch polysaccharides and fat (OR 1.49, 95% CI: 0.85, 2.63). These findings reveal differences in breast cancer risk between South Asian ethnic subgroups, which were not fully explained by reproductive differences, but were partly accounted for by diet and body size.

Breast cancer survival in women of African descent living in the US and in the Caribbean: effect of place of birth

“…There are still unmeasured factors that could be responsible for the observed differences in outcome. A study conducted in England [17] showed that differences in breast cancer risk among groups defined by place of birth, first language, and religion were attenuated when reproductive, socioeconomic, anthropometric, and dietary factors were introduced in the statistical model. Comorbidities, an additional factor contributing to both outcome and therapeutic choices, are not routinely recorded by the cancer registries.…”

Breast cancer incidence, stage, treatment and survival in ethnic groups in South East England

“…For example, McCormack et al (2004) examined groups defined by place of birth (including area within country), first language and religion. The associations between these groups and risk of breast cancer lost their significance after adjustment for reproductive, socioeconomic, anthropometric and dietary factors.…”

Breast Cancer Survival among South Asian Women in California (United States)

“…Despite these compelling statistics, very little is known about breast cancer morbidity and mortality in this growing community. Although research has been conducted on breast cancer epidemiology and survival in other Asian-American groups [3][4][5][6][7][8], studies specific to South Asians are few in number [9][10][11][12]. Previous studies have grouped all Asians into one category, which may mask important differences in incidence and survival among various subgroups.…”