Hector Avalos, in Health Care and the Rise of Christianity, makes the case that a study of the health care milieu in which Christianity arose is necessary for understanding the attraction that Christianity might have had for, particularly, the chronically ill in the Greco-Roman world.
Avalos helpfully surveys Jewish and pagan sources for indications of the values and practices surrounding sick members of those societies, particularly with respect to chronic illness. The survey of pagan culture is particularly helpful (at least for this non-Classicist) in that it enumerates the different health care options available to inhabitants of the Roman world, as well as the likely cross-pollination between Jewish monotheism and Roman paganism.
I am not conversant enough with Classical sources to know whether his presentation of health and sickness in the Roman world is accurate, but I was disappointed with his survey of Judaism. He dealt almost exclusively with the canonical texts, and seemed to weigh the New Testament critiques of Pharisaism rather more heavily than may be warranted. He did not seem to make use of more modern (and more charitable) studies of Jewish culture in the Second Temple period.
Additionally, his reading of the canonical texts was deeply problematic. He seems to have found in the texts a deep concern for protecting the state (meaning, especially, the levitical priestly hierarchy) from the burden of the chronically ill and underproductive. He takes the strict regulations concerning purity and contamination to be less interested in regulating the spread of contagious illnesses than in isolating and stigmatizing those with chronic illnesses which left them unable to be economically productive. His evidence for this interest is scant--he makes the point that the gradated requirements for thanksgiving offerings after healing (as in Leviticus 14) acknowledge the possibility that chronic illness may render a person economically unproductive, but he implies that levitical regulations are intended to marginalize those persons who have become poor.
He seems to have missed the deep concern for the poor and economically unproductive evident throughout, especially, the priestly code. The passage in question, for example, could be read as a particular effort to include those who have become poor through chronic illness and to mitigate the effects of their disadvantaged position. Economic disadvantage and unproductivity, in other words, is not an impediment to participation in the liturgical life of the community. Chronic illness is, to be sure, but there is little to no evidence that the Jewish community isolated and stigmatized the economically unproductive on a regular basis. Contagion and purity concerns are a much more convincing read of the levitical regulations regarding blood and bodily fluids.
That said, his more basic point is quite sound: whether or not such was the intention of the levitical code, and whether or not the Second Temple Jewish community practiced the levitical code exactly as written, the effect of the canonical regulations concerning chronic illnesses was to create a sub-group of people who would be particularly interested in the healing ministries of Christian missionaries, as well as the theological commitment to non-isolation of "sinners" and lepers.
Both Judaism and paganism, by Avalos's read, created a demographic group of disaffected members of society that would be attracted to Christianity precisely because it rejected (at least in its canonical texts) the very practices that had isolated them from their own societies. This partly explains, Avalos contends, the tremendous growth in the first decades after the death of Christ.