EFFECTS OF SMOKING CESSATION ON INSULIN AND CARDIOVASCULAR RISK-FACTORS - A CONTROLLED-STUDY OF 4 MONTHS DURATION

Objectives. To investigate the effects on serum lipids, plasma fibrino gen, plasma insulin, plasma C-peptide and blood glucose, of smoking ce ssation after 4 months. To develop a group-based smoking intervention programme in primary health care. Setting. Twenty health centres in pr imary health care in southern Sweden. Subjects. Four hundred habitual smokers (>10 cigarettes per day(-1), >10 years), recruited by advertis ement in local papers. Intervention. The smokers were randomized, afte r stratification for age and sex, to one intervention group (n=200) an d one control group (n=200). The intervention group was offered suppor tive group sessions and free nicotine supplementation (patches, chewin g gum). Main outcome measures. All participants were investigated at t he start and after 4 months (medical history, physical examination, la boratory evaluation), Blood samples were drawn for determination of gl ucose, insulin and C-peptide, both in the fasting state and during an oral glucose tolerance test (OGTT), and for measurement of lipoprotein s, fibrinogen, nicotine and cotinine. Results. In the intervention gro up 98 of the subjects (48%) had quit smoking after 4 months. They were compared with the 156 subjects in the control group (91%) who were st ill daily smokers during the whole period, There were no significant d ifferences in any variable between the two (total) experimental groups at baseline. Plasma nicotine and cotinine decreased (P <0.001) in the intervention group following smoking cessation, and weight increased by 2.7 kg, In the intervention group HDL-cholesterol increased by 11% (P <0.001), whereas HbA(1c) increased by 2% (P <0.05) only in the cont rol group. No changes occurred in levels of glucose, insulin, C-peptid e and fibrinogen. Conclusion. The smoking cessation programme had a su ccess rate of almost 50% over 4 months. Smoking cessation was associat ed with a marked increase in HDL-cholesterol levels but did not affect glucose tolerance, A concomitant weight increase may have blunted any independent beneficial effect of smoking cessation on glucose metabol ism.