Helsinki Heart Study. New perspectives in the prevention of coronary heart disease.

The Helsinki Heart Study tested the effect of modifying plasma low density lipoprotein (LDL)- and high density lipoprotein (HDL)-cholesterol on the primary prevention of coronary heart disease in middle-aged men with non-HDL-cholesterol greater than or equal to 5.2 mmol/L (200 mg/dl). One group (2046 men) received 600mg of gemfibrozil twice daily, and the other (2035 men) received placebo. Averaged over the 5-year trial period, gemfibrozil induced mean decreases of 11% in LDL-cholesterol and 35% in triglycerides and a mean increase of 11% in HDL-cholesterol compared with placebo. These changes were accompanied by a 34% reduction (number of end-points; 56 vs 84) in the incidence of coronary heart disease. The reduction was largest in subjects with type IIB hyperlipoproteinaemia and smallest in subjects with type IIA hyperlipoproteinaemia. The changes in serum HDL- and LDL-cholesterol during the trial were associated (p less than 0.02 and p less than 0.05, respectively) with the risk of coronary heart disease in the gemfibrozil group, but not in the placebo group.

The sense of coherence, occupation and the risk of coronary heart disease in the Helsinki Heart Study.

The risk of coronary heart disease (CHD) was studied in 4405 Finnish middle-aged working men in different occupations according to their sense of coherence (SOC). The study design was prospective and the follow-up time was eight years. Clinical findings such as total cholesterol, systolic blood pressure and body-mass index showed differences when comparing blue and white collar workers. Lifestyle factors such as smoking also differed, but leisure time physical activity depended on SOC. In the white collar work environment the low SOC tertile had a high CHD incidence of 20.1 per 1000 person-years; the incidences in the medium and high SOC tertiles were 10.9 and 12.3, respectively. A similar effect was not observed in the blue collar work environment. There, contrary to theoretical expectations, the low SOC tertile had the lowest incidence of CHD. The difference in the CHD incidence pattern depended on the blue and white collar dichotomy and not on the branch (state agencies vs. industry). The SOC had a salutogenic effect among white collar workers, but failed to have any consequent effect on the health of blue collar workers. Further study is needed to look at the psychosocial factors among blue collar workers.

Combined effects of shift work and life-style on the prevalence of insomnia, sleep deprivation and daytime sleepiness.

OBJECTIVES: The combined effects of age, leisure-time physical activity, smoking, alcohol consumption, and different forms of shift work on the prevalence of sleep complaints and daytime sleepiness were studied among workers in industry, transport, and traffic. METHODS: Altogether 3020 subjects were studied using a psychosocial questionnaire. The participants were currently employed men, aged 45-60 years, from a postal and telecommunication agency, the railway company, and 5 industrial companies. On the basis of a factor analysis of an 11-item sleep questionnaire, the sleep complaints were grouped into the categories of insomnia, sleep deprivation, daytime sleepiness, and snoring. The importance of the shift schedule, age, and life-style factors as simultaneous predictors of the complaints was studied in a logistic regression analysis and an analysis of covariance. RESULTS: The prevalence of insomnia, sleep deprivation, and daytime sleepiness depended significantly on the shift system. All sleep complaints were more common in 2- and 3-shift work and in irregular shift work than in day work. The prevalence of daytime sleepiness was 20-37%, depending on the shift system. Leisure-time physical activity and alcohol consumption were the most important life-style factors predicting all sleep complaints, except snoring. The effects of physical activity and alcohol consumption differed for different shift schedules. CONCLUSIONS: Different shift systems, also 2-shift work and permanent night work, seem to increase the frequency of sleep complaints. Especially 3-shift work seems to interact with life-style factors by increasing the adverse effects and decreasing the beneficial effects on sleep and sleepiness.

Lipid alterations and decline in the incidence of coronary heart disease in the Helsinki Heart Study.

In the Helsinki Heart Study, a randomized five-year, double-blind trial, a 34% reduction in the incidence of coronary heart disease (CHD) was observed in dyslipidemic men treated with gemfibrozil. Averaged over the five years of the trial, gemfibrozil therapy produced, compared with placebo, mean decreases of 10% in serum total cholesterol level, 14% in non-high-density lipoprotein (HDL) cholesterol level, 11% in low-density lipoprotein (LDL) cholesterol level, 35% in triglyceride level, and a mean increase of 11% in HDL cholesterol level from baseline levels measured prior to treatment. While changes in HDL cholesterol level were similar in all Fredrickson types, the effect on concentrations of total cholesterol and LDL cholesterol was largest in type IIA and on LDL minimal in type IV. The reduction of CHD incidence over placebo was largest in type IIB and smallest in type IIA. The lipid changes were dependent on lipid levels prior to treatment and on compliance with the medication regimen. When risk factors for CHD, including age, blood pressure, smoking and drinking habits, baseline lipid levels, and exercise and relative weight, were controlled by applying the Cox proportional hazards model, the changes in serum HDL and LDL cholesterol levels were both statistically significantly associated with the decline in CHD incidence within the gemfibrozil-treated group. The large decrease in serum triglyceride levels had relatively small effect on CHD incidence. Thus, the results of this study, together with earlier observations, suggest that both elevating HDL and lowering LDL cholesterol levels are effective in the primary prevention of CHD.

The Helsinki Heart Study: basic design and randomization procedure.

The Helsinki Heart Study is a coronary primary prevention trial in a group of middle aged men with lipid abnormalities. Its aim is to investigate the effects on the incidence of coronary heart disease of simultaneously lowering serum total and low density lipoprotein (LDL)-cholesterol and elevating high density lipoprotein (HDL)-cholesterol with gemfibrozil, over a period of 5 years. Participants were selected from a population of 23 531 men between 40 and 55 years of age. The mean serum total cholesterol among 18 966 screened subjects was 6.3 mmol l-1 (245 mg dl-1) and the mean HDL-cholesterol 1.3 mmol l-1 (50.3 mg dl-1). All subjects meeting the lipid acceptance criterion of non-HDL-cholesterol (i.e. total cholesterol minus HDL-cholesterol) greater than 5.2 mmol l-1 (200 mg dl-1) on two separate occasions two to three months apart, who were free from coronary heart disease or other major illness, were invited to participate. The total cholesterol level for the final 4081 study participants was 7.5 mmol l-1 (290 mg dl-1) and HDL-cholesterol was 1.23 mmol l-1 (47.6 mg dl-1). Mean systolic and diastolic blood pressures were 141.7 and 91.3 mmHg. About 15% of participants were hypertensive and 36% were smokers. A total of 2051 men were randomly allocated to receive gemfibrozil 600 mg twice daily and 2030 matching placebo capsules. A cholesterol-lowering diet was also prescribed for all participants. The randomized treatment groups were well balanced. Equal distribution of major risk factors was achieved in relevant sub-groups. This report describes the procedures involved in setting up the study, summarizes the baseline data obtained and reviews the success of the randomization procedure. Finally, it compares the design of this study with that of some other major preventive trials.

Helsinki Heart Study: primary-prevention trial with gemfibrozil in middle-aged men with dyslipidemia. Safety of treatment, changes in risk factors, and incidence of coronary heart disease.

In a randomized, double-blind five-year trial, we tested the efficacy of simultaneously elevating serum levels of high-density lipoprotein (HDL) cholesterol and lowering levels of non-HDL cholesterol with gemfibrozil in reducing the risk of coronary heart disease in 4081 asymptomatic middle-aged men (40 to 55 years of age) with primary dyslipidemia (non-HDL cholesterol greater than or equal to 200 mg per deciliter [5.2 mmol per liter] in two consecutive pretreatment measurements). One group (2051 men) received 600 mg of gemfibrozil twice daily, and the other (2030 men) received placebo. Gemfibrozil caused a marked increase in HDL cholesterol and persistent reductions in serum levels of total, low-density lipoprotein (LDL), and non-HDL cholesterol and triglycerides. There were minimal changes in serum lipid levels in the placebo group. The cumulative rate of cardiac end points at five years was 27.3 per 1,000 in the gemfibrozil group and 41.4 per 1,000 in the placebo group--a reduction of 34.0 percent in the incidence of coronary heart disease (95 percent confidence interval, 8.2 to 52.6; P less than 0.02; two-tailed test). The decline in incidence in the gemfibrozil group became evident in the second year and continued throughout the study. There was no difference between the groups in the total death rate, nor did the treatment influence the cancer rates. The results are in accord with two previous trials with different pharmacologic agents and indicate that modification of lipoprotein levels with gemfibrozil reduces the incidence of coronary heart disease in men with dyslipidemia.