No sex differences in immunisation rates of British south Asian children: the effect of migration?

Introduction

In most countries male mortality exceeds female mortality at every age. In parts of northern Africa, the Middle East, and the Indian subcontinent, however, where life expectancy is relatively low, female mortality at 0-4 years exceeds that of males.1 Discrimination against girls in India is blatant in the selective abortion of female fetuses.2 Girls also have poorer access to health services than boys: in Bombay boys have immunisation rates 16% higher than girls.3 We do not know whether these sex differences in health service uptake occur in British residents whose ethnic origins lie in the Indian subcontinent (south Asians). To answer this question we conducted a historical cohort study comparing immunisation uptake in south Asian and European children living in Newcastle.

Methods and results

South Asian populations in Newcastle–Of the 259 541 residents of Newcastle at the 1991 census, 2176 reported their ethnic origin as Indian, 2913 as Pakistani, and 1300 as Bangladeshi. About half of Newcastle Indians and Pakistanis and 30% of Bangladeshis were born in the UK. Most Pakistanis and Bangladeshis are Moslem and live in the economically disadvantaged “west end” of Newcastle. Most Indians are Hindus and Sikhs and are more widely dispersed.

The study investigated the uptake of complete courses of triple vaccine; measles, mumps, and rubella vaccine; and BCG immunisation in the first two years of life, as recorded by the Newcastle child health register. The family health services authority register recorded 12 867 children born in Newcastle from 1 January 1989 to 28 February 1993–that is, after the introduction of measles, mumps, and rubella immunisation in 1988 and old enough to have received it by the start of data collection on 1 March 1995. A name search identified 346 Moslem south Asians and 115 Hindus and Sikhs who were matched for age, sex, and general practitioner to 461 children of European origin. The power of this study to detect a 16% sex difference in immunisation rate (as reported by Naik3) was 99%. The Mann-Whitney test was used to compare differences in age at immunisation;95% confidence intervals were calculated for differences in immunisation rate.

table 1 shows no important sex differences in immunisation uptake for any ethnic group. Only one of the 24 comparisons of immunisation uptake by sex was significantly different (measles, mumps, and rubella in non-Moslem south Asians; 95% confidence interval for the difference between boys and girls: 0 to 13%). Median age at completion of immunisation was generally higher in girls, but the differences were small and not significant.

Comment

Overall, rates of immunisation uptake were high for all groups of children. Indeed, as in Glasgow,4 south Asians in Newcastle had higher immunisation rates than Europeans. There are two alternative explanations for the lack of sex differences in this study. Firstly, it is possible that no sex differences would have existed in this population of south Asians if they had not migrated. Secondly, and plausibly, migration may have been a factor in eliminating behaviour which determines sex differences. Free medical care in Britain and the relative affluence of life in Newcastle compared with the Indian subcontinent may have played a part. If so, sex differences on the Indian subcontinent might be expected to disappear as health services improve and populations become more affluent. Nevertheless, sex differences in the Indian subcontinent are seen where women have low status, even in wealthy families and when medical care is free.5 Absence of sex differences in Newcastle south Asians may therefore reflect changes in culture as well as in material circumstances. While this interpretation warrants debate, our findings suggest that sex differences in health care use in British south Asian children are absent or insignificant and provide hope that such differences on the Indian subcontinent are amenable to change.