Social determinants of nutrient intake in smokers and non-smokers during pregnancy.
STUDY OBJECTIVE--The aim was to investigate the effects of social factors (education, income, marital status, partners' employment status, housing tenure, social class), smoking, and maternal height on the dietary intake of pregnant women. DESIGN--The study was a prospective investigation on a two phase sample. SETTING--The study involved women attending the antenatal clinic at a district general hospital. PATIENTS--A group of pregnant Caucasian women, selected because they were heavy smokers (15+ cigarettes/day) (n = 94) and a randomly selected sample of never smokers (n = 112) were studied. MEASUREMENTS AND MAIN RESULTS--Data on social factors were collected by interviewer administered questionnaire. A 7 day weighed intake method was used to determine dietary intake at 28 weeks gestation. In univariate analyses, income, housing tenure and social class had significant effects on intakes of both macro- and micronutrients, and maternal education and smoking had significant effects on intakes of micronutrients. Using a stepwise multivariate analysis with income, smoking and maternal education, income was a significant factor in the intake of most nutrients but this effect disappeared when social class and housing tenure factors were entered into the model. Only social class and housing tenure had any significant effect on intakes of macronutrients--energy, protein and fat. Smoking and maternal education were the most important determinants of quality of diet (nutrient density); other factors had only negligible effects. Income was the only significant factor in alcohol intake. It is suggested that the effects of social class and income are overlapping. CONCLUSIONS--Smoking, being renters of accommodation, and being of minimum education and low social class are risk factors for poor dietary intake. It is recommended that such higher risk groups be specifically targeted for nutritional advice in pregnancy.