Among the 50 trials, 30 were primary prevention trials (general populations,
smokers and workers exposed to asbestos, patients with oesophageal dysplasia, male physicians, patients with non-melanoma skin cancer, postmenopausal
women, patients undergoing chronic haemodialysis, patients with end stage renal disease, ambulatory elderly
women with vitamin D insufficiency, patients with chronic renal failure, older people with femoral neck fractures, patients with diabetes mellitus, elderly
women with a low serum 25 - hydroxyvitamin D concentration, health professionals, people with a high fasting plasma total homocysteine concentration, or kidney transplant recipients), and 20 were secondary prevention trials (patients with cardiovascular disease, coronary heart disease, acute myocardial infarction, unstable angina, transient ischaemic attack, stroke, angiographically proved coronary atherosclerosis, vascular disease, or aortic valve stenosis).
First, given the higher rate of refusal to participate in the study
among women who smoked cigarettes, this trial has limited generalizability to the entire population of
smokers and probably users of other substances.
2 Comparison of demographic and other characteristics for
smokers and non-
smokers among 302 pregnant Australian Indigenous
women attending the Mums and Babies program at the Townsville Aboriginal and Islander Health Service between 1 November 2005 and 31 October 2007
Among Indigenous
women who did smoke during pregnancy, most were light
smokers but tended to live with a higher number of other household
smokers than did
women who did not smoke during pregnancy.
Our findings are consistent with those of other researchers who found that, while Indigenous
women who smoke during pregnancy have low to medium nicotine dependency, 16,23 the number of
smokers in the household is significantly associated with smoking
among pregnant Indigenous
women.24