Several mechanisms may underlie convergence in racial/ethnic differences in smoking and, for women, marijuana use across the lifecourse. First, our results as well as results of others suggest that two simultaneous mechanisms may underlie smoking convergence: White young adults are more likely to cease smoking in young adulthood (Barbeau et al., 2004; King et al., 2004), and the average age of onset of smoking is later for Blacks than for Whites (Geronimus et al., 1993; Kandel et al., 2011; Moon-Howard, 2003). This pattern also holds for marijuana (Finlay et al., 2012). This combined later onset of smoking and lower cessation at least partially underlies the convergence in young adulthood. Second, substantial evidence has supported a ‘weathering’ hypothesis for Blacks in the US (Geronimus, 1992). That is, the cumulative stress of disadvantage and chronic exposure to discrimination through the lifecourse portends greater adverse health consequences at relatively earlier points in the lifecourse compared with Whites, and adoption of problematic health behaviors such as smoking at later points in the lifecourse to mitigate the experiences chronic stress. Combined, this literature indicates that
