Elsevier

The Lancet

Volume 351, Issue 9107, 28 March 1998, Pages 934-939
The Lancet

Articles
Mortality differences between black and white men in the USA: contribution of income and other risk factors among men screened for the MRFIT*

https://doi.org/10.1016/S0140-6736(05)60603-4Get rights and content

Summary

Background

Studies of underlying differences in adult mortality between black and white individuals in the USA have been constrained by limitations of data or small study size. We investigated the extent to which differences in socioeconomic position between black and white men contribute to differences in all-cause and cause-specific mortality.

Methods

361 662 men were screened for the Multiple Risk Factor Intervention Trial between 1973 and 1975, in 22 sites. Median family income of households by zipcode (postal) area of residence was available for 20 224 black and 300 685 white men as well as data on age, cigarette smoking, blood pressure, serum cholesterol, previous heart attack, and treatment for diabetes. We classified deaths during 16 years of follow-up into specific causes and compared differences in death rates between black men and white men, before and after adjustment for differences in income and other risk factors.

Findings

Age-adjusted relative risk of death (black vs white) was 1·47 (95% CI 1·42–1·53). Adjustment for diastolic blood pressure, serum cholesterol, cigarette smoking, medication for diabetes, and previous admission to hospital for heart attack decreased the relative risk to 1·40 (1·35–1·46). Adjustment for income but not the other risk factors decreased the risk to 1·19 (1·14–1·24) and adjustment for other risk factors did not alter this estimate. For cardiovascular death, relative risk on adjustment for income was decreased from 1·36 to 1·09; for cancer from 1·47 to 1·25; and for non-cardiovascular and non-cancer deaths from 1·71 to 1·26. For some specific causes of death, including prostate cancer, myeloma, and hypertensive heart disease, the higher death rates among black men did not seem to reflect differences in income. Rates of death for suicide and melanoma were lower among black than white men, as were those for coronary heart disease after adjustment for income.

Interpretation

Socioeconomic position is the major contributor to differences in death rates between black and white men. Differentials in mortality from some specific causes do not simply relect differences in income, however, and more detailed investigations are needed of how differences are influenced by environmental exposures, lifetime socioeconomic conditions, lifestyle, racism, and other sociocultural and biological factors.

Introduction

The difference in death rates between black and white men in the USA is large and is increasing.1 The persistence of this inequality is a major public-health concern and investigations of this issue within the social-medicine framework have a long history.2 Various approaches have been taken in the assessment of black-white health differences. First, “race” has been used as a proxy for socioeconomic position in much official health data. Therefore, in the Department of Health and Human Services' report on “Health status of the disadvantaged”, many tables present health indicators by “race” and not by any direct socioeconomic measure. Second, black-white differences in some specific diseases, such as coronary heart disease and hypertension, have been investigated in detail in an attempt to understand disease aetiology, but classification has also generally been by “race”, without taking into account socioeconomic position. Third, some attempts have been made to quantify the contribution of socioeconomic position and other indicators of mortality risk to black-white differences.4

Studies of factors underlying differences in adult mortality between black and white people have been limited either by lack of data beyond basic demographic characteristics, or by small study size, which allows investigation of only a few major causes of death. We investigated differences in death rates among men screened for the Multiple Risk Factor Intervention Trial (MRFIT). Because of the large size of this cohort we were able to assess the contribution of socioeconomic position and other risk factors to differences in mortality from a wide variety of causes.

Section snippets

Methods

From November, 1973, to November, 1975, 361 662 men aged 35–47 years were screened at 22 MRFIT clinical centres in 18 cities in the USA. For recruitment, centres used a variety of methods, including house-to-house canvassing; screening of government, industrial, or other employee populations; and through civic groups, unions, and churches.5

Each participant gave information on name, address, date of birth, social security number, and number of cigarettes smoked per day. Participants reported

Results

Characteristics for black and white men are presented in table 1. Black men were slightly younger, had higher systolic and diastolic blood pressures and frequency of hypertension, and had lower serum cholesterol concentrations than white men. More black men smoked, but white men smoked more cigarettes per day. A higher proportion of black men were taking medication for diabetes. Zipcode areas of residence were strikingly different within each group by: median family income, proportion of

Discussion

The consistency of the differences in mortality between black men and white men across the 22 MRFIT sites suggests that our findings are robust and generalisable. Adjustment for income substantially decreased the raised risk of all-cause mortality among black men. Several findings indicate that the mortality experience of these men provides a useful model for exploration of factors underlying differences in the general population. The difference in median family income by area of residence for

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  • Cited by (0)

    Rose Stamler died February, 1998

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