That absolute poverty is one of the key reasons behind poor health is an accepted truth. What could, and does, appear counter-intuitive, though, is the claim that high levels of income inequality within a population group leads to unconsoinably wide disparities with regard to health outcomes, even when the general levels of income across that group are fairly high. But an article in the Economic and Political Weekly (August 2-8, 2008), based on National Family Health Survey-3 (NFHS-3) data on various child health indices, has substantiated this direct correlation between levels of relative income inequality and differential in health outcomes.
It comes up with measures of income-linked health inequalities across various Indian states by calculating the concentration index (CI) for key child health indicators — under-five mortality rate, stunting, underweight, prevalence of anaemia and not fully immunised — for each of those states. The CI ranges between +1 and -1, whereby an increase in negative value signifies an increasing disproportion in concentration of ill-health among the poor.To understand the concept of CI, we need to discuss the idea of concentration curve (CC).
CC plots the cumulative proportions of the population (starting with the most income-poor and ending with the least) on the x-axis against the cumulative proportions of ill-health with regard to any one particular parameter like, say, under-five mortality rate, on the y-axis. In such a graph, if the burden of poor health is equally distributed across socio-economic strata, the CC would be a diagonal. However, as the concentration of poor health among lower socio-economic sections increases, the distance between the egalitarian diagonal and the CC increases with the latter lying above the former. The value of CI, which is nothing but twice the area between the CC and the egalitarian diagonal, becomes more and more negative as the distance between them widens.
The under-five mortality CC for all-India and those of three major states (Maharashtra, Gujarat and Madhya Pradesh) with higher income-linked health inequality levels, lie above the diagonal, indicating a greater concentration of ill-health among the poorer groups. But what is really revealing is that the level of income-linked health inequality in Gujarat — where across-the-board absolute prosperity is much higher than in most other Indian states — is much more than what it is for the country as a whole. The Gujarat under-five mortality CC is only marginally below Madhya Pradesh’s, whose absolute level of economic prosperity is among the lowest, and above Maharashtra’s.
The EPW article shows that all-India CI values for all the child health variables mentioned above are negative. Much more startling, however, are instances of states — such as West Bengal, Uttar Pradesh, Rajasthan and Bihar — with low levels of absolute prosperity displaying lower levels of both income inequality and related inequity in health outcomes than states like Maharashtra, Gujarat, Tamil Nadu and Punjab. The CI value for the NFHS-3 variable of under-five mortality — which is -0.1582 for the entire country taken together — is -0.0388, -0.0960, -0.0801, -0.08282 for West Bengal (all-India lowest), UP, Rajasthan and Bihar, while for Maharashtra, Gujarat, Tamil Nadu and Punjab it is -0.2481, -0.2193, -0.1749 and -0.1688.
The article also observes that Punjab, Maharashtra, Gujarat and similar states have higher levels of income along with higher levels of health inequalities, whereas states such as UP, Bihar and Orissa with lower income levels have lower level of health inequalities. But the relationship is, fortunately enough, not always so straightforward. Madhya Pradesh, J&K, Manipur, Mizoram, Nagaland, Tripura and Uttaranchal (states with low income and high health inequality), and Karnataka, Kerala, and Haryana, Sikkim (states with higher income and lower health inequality) spoil the elegance of the equation.
It concludes that the levels of income inequality directly determine levels of health inequality much more in a scenario of overall higher levels of income. It also follows, therefore, that in a scenario of generally lower incomes and high-income inequality, the inequality in health outcomes would be greater than if income levels are higher and income inequality levels are lower.