Introduction: We evaluated associations between ecological variables and the risk of very small for gestational age ( VSGA ) birth in Quebec in 2000–2008.

Methods: Ecological variables came from the Canadian Community Health Survey, the Canadian census and Quebec's birth registry; individual variables also came from Quebec's birth registry. Odds ratios ( OR s) adjusted for mother's age, academic qualification, parity, marital status and country of birth were estimated using multilevel logistic regression (generalized estimating equations method).

Results: Births in neighbourhoods with a high proportion of people leading a sedentary lifestyle ( OR : 1.07, 95% confidence interval [ CI ]: 1.01–1.11) and those with a high/ middle proportion of residents with food insecurity ( OR : 1.09, 95% CI : 1.05–1.15; OR : 1.05, 95% CI : 1.01–1.11) had higher odds of VSGA birth. Those with middle proportion of married residents had lower odds of VSGA birth ( OR : 0.94, 95% CI : 0.90–0.98).