Moderating effect of gross family income on the association between demographic indicators and active commuting to work in Brazilian adults.

Objective: To investigate the moderating effect of gross family income on the association between demographic indicators and active commuting to work in Brazilian adults.

Methods: Secondary analysis of the survey "Lifestyle and leisure habits of industry workers" (n=46,981), conducted in 24 Brazilian states (2006-2008). Self-reported information was collected with a previously tested questionnaire. Crude and adjusted logistic regression models were applied to analyze the association between sociodemographic variables (sex, age, marital status, number of children, education, country area and company size) and active commuting to work in different strata of gross family income. To test the moderating effect, an interaction analysis was applied.

Results: The proportion of active commuters among low-, medium- and high-income workers was 40.7% (95%CI:40.0%;41.5%), 27.0% (95%CI:26.3;27.6%) and 11.1%, (95%CI:10.5%;11.7%), respectively. The moderating effect of gross family income was confirmed. Men were more likely (OR:1.22 95%CI:1.12;1.32) to commute actively than women among low-income individuals. Active commuting was less likely among older workers in low-(OR30-39:0.90 95%CI: 0.83;0.98; OR≥40: 0.76 95%CI: 0.68;0.85) and medium-income strata (OR30-39:0.87 95%CI:0.80;0.95; OR≥40:0.84 95%CI:0.76;0.93) and among married individuals in high-income strata (OR:0.72 95%IC:0.61;0.84). Adults with lower education (ORhigh:10.80 95%CI:8.47;13.77), working in the south (ORhigh:1.93 95%CI:1.53;2.44) and in small companies (ORlow:2.50 95%CI:2.28;2.74) were more likely to commute actively; however, the magnitude of these associations differed at each income strata.

Conclusion: There was an inverse association between gross family income and active commuting. Gross family income acts as a moderator of the association between demographic indicators and active commuting.