Inequalities in self-rated health: explanations from different stages of life

doi:10.1016/S0140-6736(97)11082-0

The Lancet

Volume 351, Issue 9108, 4 April 1998, Pages 1009-1014

https://doi.org/10.1016/S0140-6736(97)11082-0 Get rights and content

Summary

Background

Inequalities in health are a major public-health concern. A greater understanding is needed on the relative importance of different causes. We investigated the contribution of risk factors identified at different life stages to inequalities in self-rated health.

Methods

We used data from 5606 men and 5799 women in the 1958 British birth cohort followed-up to age 33 years, on health behaviour, education, adolescent health, family structure and social support, work characteristics, and material circumstances. We assessed the contribution of different factors to social-class differences in self-rated health by adjustment of odds ratios (classes IV and V vs I and II).

Findings

Odds ratios of poor-rated health at age 33 were 3·15 for men and 2·30 for women, which decreased to 2·06 and 1·34, respectively, after adjustment for previously identified factors from birth to early adulthood. Adjustment for adult work characteristics, material circumstances, and health behaviour between ages 23 years and 33 years further decreased the odds ratios to 1·64 (men) and 1·11 (women). Most factors contributed to the reduction in odds ratios, although adolescent socioemotional adjustment, class at birth, educational qualifications, and psychosocial job strain were especially important. Additional key factors for men were adult smoking and job insecurity, and for women, housing during childhood, adult income, and age at first child.

Interpretation

There was no single cause of health inequality at age 33 years. Explanations spanned from early life to young adulthood. Policy implications include reduction of social differences in material circumstances and of differences in individual skills and resources acquired in early life.

Introduction

Understanding of the causes of inequalities in health has progressed1, 2 but still too little is known about the relative importance of different explanations. Research has expanded on the four main explanations presented in the Black Report³ (artefact, selection, lifestyle, and material circumstances), to emphasise distribution, accessibility, and quality of medical care,2, 4 factors early in life,⁵ psychosocial factors,⁶ and social cohesion.⁷ Collectively, this research suggests that explanations vary by sex and lifestage and for different causes of mortality and morbidity.⁸

Evidence on long-term and cumulative influences on inequalities is sparse, primarily because few studies take account of lifetime circumstances or duration of exposure to particular risk factors. An exception is Power and colleagues' investigation of inequalities in early adulthood, based on the 1958 British birth cohort.⁹ They showed that an accumulation of diverse factors from birth to age 23 years contributed to subsequent inequalities. An analysis of the cohort at age 33 years provided further support for this conclusion, but focused mainly on the role of health-related social mobility, with limited representation of lifetime risks.¹⁰ The need for a detailed investigation of specific influences was recognised. We aimed to provide such a detailed analysis of the 1958 birth cohort to provide explanations for inequalities in self-rated health at age 33 years. We assessed whether factors identified in relation to inequalities at age 23 years⁹ remained important 10 years later. We also investigated the contribution of additional explanatory factors between ages 23 years and 33 years.

During these 10 years, many factors are likely to have had an impact on health. This period is one of transition, in which many individuals in the UK complete their education, gain employment, leave the family home, and start their own family. We selected factors known to have adverse health effects as potential explanations for health inequalities. By taking into account more specific factors, we were able to extend previous investigations of inequality in this cohort.

Section snippets

Methods

The 1958 British birth cohort includes all children born in England, Wales, and Scotland from March 3 to 9, 1958. The original Perinatal Mortality Study recorded information on 17414 (98%) births, with follow-up surveys at ages 7 years, 11 years, 16 years, 23 years, and 33 years (11405 people were interviewed in 1991: 5606 men and 5799 women).¹¹ In general, the people remaining in the study were representative of the original sample.9, 11 We assessed response biases specifically for the study

Results

We found a significant social gradient in poor health by age 23 years, ranging from 5·3% of men in social classes I and II to 10·5% in classes IV and V; for women, the range was from 5·2% to 13·9%. The gradient persisted to age 33 years, ranging from 8·5% in men in classes I and II to 17·7% in classes IV and V; and in women from 9·4% to 18·8% (table 1).

Odds ratios previously calculated for poor health for participants in classes IV and V relative to classes I and II at age 23 years, adjusted

Discussion

For this cohort, we have previously established that social gradients in poor health exist in early adulthood; these gradients remain constant from ages 23 years to 33 years, and seem to be explained by lifetime socioeconomic circumstances.9, 10, 15 Previous analyses did not assess the specific life-course factors that might explain inequalities at age 33 years or show whether factors identified in relation to health inequalities at age 23 years would be relevant to inequalities 10 years later

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ArticlesInequalities in self-rated health: explanations from different stages of life

Summary

Background

Methods

Findings

Interpretation

Introduction

Section snippets

Methods

Results

Discussion

Lancet

Soc Sci Med

Soc Sci Med

J Health Econ

Lancet

The Black Report on socioeconomic inequalities in health 10 years on

BMJ

Tackling inequalities in health

Inequalities in health: the Black Report and the health divide

Explanations for social inequalities in heath

Inequalities in health in Britain: specific explanations in three Lancashire towns

Health inequalities: relative or absolute material standards?

BMJ

Social inequalities and health in the contemporary world: a comparative overview

Health and class: the early years

Inequalities in self rated health in the 1958 birth cohort: life time social circumstances or social mobility?

BMJ

Life at 33: the fifth follow-up of the National Child Development Study

A children's behaviour questionnaire for completion by teachers

J Child Psychol Psychiatry

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Inequalities in self-rated health: explanations from different stages of life