Jayne L. Fryer

Comparison of family history measures used to identify high risk of coronary Heart disease

We examined 15 published continuous family history measures (scores) as well as two new formulations in terms of several desirable properties. We applied the scores to sample pedigrees and found that some systematically increase with family size. In contrast to aggregate scores, non‐aggregate scores are sensitive to the age, sex, and covariate status of individual relatives but are unstable when the families are small. We also applied these scores to our own population case‐control data, characterised by a high proportion of missing and false‐negative responses. In these small families, all scores provided significant discrimination between CHD cases and controls beyond the usual categorical definition of positive family history, but appeared no better than detailed categorical definitions or even simple counts. Our new formulations offer no solution to the problems of few data; most scores apply asymptotic approximations to differences between observed and expected number of affected relatives and are not suited to small families. All scores would be improved by ruling out families with only one affected relative, as is being done in the NHLBI Family Heart Study. We recommend that researchers, when using a family history measure, consider the number of informative families and other characteristics of their data prior to choosing any particular formulation. Genet. Epidemiol. 16:344–355, 1999.

Predictors of smoking in pregnancy and attitudes and knowledge of risks of pregnant smokers

This study examined the prevalence and predictors of smoking by pregnant women attending a public antenatal clinic. The prevalence of smoking in this population (n = 2577) was found to be 38.0% (95% CI 36.1-39.9%). A review of previous research investigating variables associated with smoking in pregnancy indicated that only three of 42 studies had used multivariate analysis. Using step-wise logistic regression analysis, five variables were found to be independent predictors of smoking in pregnancy: education (having 4 years or less high school), marital status (being unmarried), gravidity (being multigravida), age (being under 25 years) and language spoken at home (speaking English). The model correctly predicted 63.7% of cases. The knowledge and attitudes of pregnant smokers were also investigated using data from a sub-sample of consenting subjects. Three-quarters of the women claimed that they had reduced their smoking since discovering they were pregnant. However, their mean intake of 13.7 cigarettes daily remained at a hazardous level. Approximately half (51%) these smokers claimed to have tried to quit smoking in the current pregnancy. Most (61%) women said they believed smoking was definitely harmful to the unborn child. However, awareness and acceptance of specific risks were inadequate. Of the women in a current relationship, 72% said their partner was a regular smoker. Less than half (45%) the continuing smokers who had seen a doctor about their current pregnancy could recall being advised to stop smoking. There is a need for health care providers to adopt a more systematic and tailored approach to smoking cessation counselling. Efforts to convert quit attempts in pregnancy into sustained cessation represent a priority area of programme development and evaluation.