The relative risk of smoking for migrants compared to the US-born group stratified by age at migration to the US by country of origin¹.

1Country of origin is country of birth, except for second generation migrants where it is the country of birth of the parents. 22nd Generation: those born in the US whose parents are both foreign-born. 3Variance between all available categories. 4No smokers in this group. *Significant (p≤0.05). **Other Africa: Ghana, Kenya and South Africa.