between community variables and individual behavior is an extremely fruitful area for behavioral and social science research. Work on these areas will be greatly enhanced by ongoing monitoring of STDs and tuberculosis by the CDC. STD and tuberculosis rates can now be measured overall and at the level of particular communities, which will significantly increase our ability to understand the role of community factors in these health outcomes.

Rates of infant mortality and low birth weight are each driven by a confluence of conditions that include low socioeconomic status; poor or no prenatal care; high-risk health behaviors (e.g., smoking, drinking, and drug abuse by pregnant mothers); and chronic exposure to violence, poverty, and nonsupportive social networks. The teen birth rate is strongly correlated with the mother having grown up in an environment in which at least four of the following six conditions held: (1) as a child she was not living with two parents; (2) the household head was a high school dropout; (3) family income was below the poverty line; (4) the parent(s) did not have steady, full-time employment; (5) the family was receiving welfare benefits; and (6) she did not have health insurance (Annie E. Casey Foundation, 1999). All the above conditions vary dramatically by state and by county in the United States. For example, the percentage of children living in families that satisfy four or more of the above high-risk conditions for teen parenthood in 1996 varied from 7 percent in New Hampshire to 21 percent in Mississippi and 39 percent in the District of Columbia.

A more subtle understanding of pathways to low-birth-weight babies, teen parenthood, and infant mortality requires multilevel analyses linking community characteristics with individual histories. Much remains to be done in this area. The recent methodological advances and recommended research priorities for Chapter 6 can be expected to play a central role in future developments.

Turning to asthma, the most common chronic disease of childhood, a deep understanding of its causes still lies in the future. Several current National Institutes of Health (NIH) initiatives are aimed at addressing this knowledge gap. The National Heart, Lung, and Blood Institute (NHLBI) has an initiative aimed at specifying how genetic and environmental factors interact in the developing lung and lead to the onset of asthma. One study sponsored by NHLBI will examine the cellular and molecular mechanisms underlying asthma's relationship with sleep and day-night events. The National Institute of Environmental Health Sciences (NIEHS) has a new Environmental Genome Project that will study different populations in different parts of the country in order to examine how interaction between