It’s well established that adults with college degrees are much less likely to smoke than adults with less education, but the reasons for this inequality are unclear. A new Yale study shows that the links between smoking and education in adulthood are in fact explained by characteristics and choices made in adolescence. The study appears in the journal Social Science Research.

The study uses data collected over 14 years to link the smoking and educational histories of adults ages 26 to 29 to their experiences in adolescence. It turns out that differences in smoking by the level of education the person will eventually complete appear as early as age 12, long before that education is obtained, writes author Vida Maralani, assistant professor of sociology at Yale.

Maralani’s study shows that educational disparities in adult smoking are anchored to experiences from early in life. School policies, peers, and expectations about the future measured at ages 13 to 15 predict smoking at ages 26 to 29. “This means that in order to reduce educational inequalities in smoking, we have to figure out exactly which characteristics before age 12 predict that a child will both not take up smoking and stay committed to school,” Maralani said.

Maralani also shows that commonly assumed explanations such as college aspirations and analytical skills do not explain the links between smoking and education in adulthood. Instead, Maralani argues, the families in which kids grow up and children’s non-cognitive skills may matter far more than realized in explaining the robust association between education and smoking in adulthood.

Maralani writes, “Overall, educational inequalities in adult smoking are better understood as a bundling of advantageous statuses that develops in childhood, rather than the effect of education producing better health.”

Funding for this study was provided by the Robert Wood Johnson Foundation Health & Society Scholars program.