Cigarette smoking and random serum cholesterol levels in a Northern Ireland general practice population of 18- to 20-year-old students and non-students.

BACKGROUND Coronary heart disease is the commonest cause of death in Northern Ireland, but few data exist on the incidence of risk factors in young adult students and non-students. AIM To gather data on the prevalence of cigarette smoking and raised serum total cholesterol in a population of 18- to 20-year-old students and non-students. METHOD Subjects were patients are Mountsandel Surgery, Coleraine on 1 January 1989 and were 18-20 years of age inclusive on that date. Subjects were interviewed by a research nurse who recorded socio-demographic data, tobacco consumption and random serum total cholesterol. Smoking status validation was by serum thiocyanate and expired air carbonmonoxide estimations. RESULTS Out of the 832 subjects surveyed, 570 were students and 262 were non-students. Cigarettes were smoked by 239 (28.7%) subjects, and a significantly greater proportion of non-students compared with students were smokers (36.6% and 25.1%, respectively; P < 0.001). The proportion of males compared with females who smoked cigarettes was not significantly different, but males smoked significantly more cigarettes per day than females (14 and 11 cigarettes, respectively; P = 0.005). The average age for commencing regular cigarette smoking was 15.3 years, and 49.9% of smokers had started regular smoking by the age of 16 years. A greater proportion of non-students (65.7%) compared with students (39.2%) had started smoking before the age of 16 years. Out of those sampled, 156 (19.2%) had random serum cholesterol levels above 5.2 mmol l-1. Mean total cholesterol for non-students was significantly higher than for students (4.61 and 4.45 mmol l-1, respectively; P = 0.01) and increased significantly with increasing age (P = 0.03). Three subjects recorded cholesterol levels above 7.8 mmol l-1. CONCLUSION Cigarette smoking and raised serum total cholesterol were prevalent among an apparently healthy population of students and non-students. These young adults may be significantly more at risk from subsequent coronary heart disease than was previously suspected.