Urinary sodium excretion and cardiovascular mortality in Finland: a prospective study.

BACKGROUND: The evidence that high salt intake increases the risk of cardiovascular disease has been challenged. We aimed to find out whether salt intake, measured by 24 h urinary sodium excretion, is an independent risk factor for cardiovascular disease frequency and mortality, and all-cause mortality. METHODS: We prospectively followed 1173 Finnish men and 1263 women aged 25-64 years with complete data on 24 h urinary sodium excretion and cardiovascular risk factors. The endpoints were an incident coronary and stroke event, and death from coronary heart disease, cardiovascular disease, and any cause. Each endpoint was analysed separately with the Cox proportional hazards model. FINDINGS: The hazards ratios for coronary heart disease, cardiovascular disease, and all-cause mortality, associated with a 100 mmol increase in 24 h urinary sodium excretion, were 1.51 (95% CI 1.14-2.00), 1.45 (1.14-1.84), and 1.26 (1.06-1.50), respectively, in both men and women. The frequency of acute coronary events, but not acute stroke events, rose significantly with increasing sodium excretion. When analyses were done separately for each sex, the risk ratios were significant in men only. There was a significant interaction between sodium excretion and body mass index for cardiovascular and total mortality; sodium predicted mortality in men who were overweight. Correction for the regression dilution bias increased the hazards ratios markedly. INTERPRETATION: High sodium intake predicted mortality and risk of coronary heart disease, independent of other cardiovascular risk factors, including blood pressure. These results provide direct evidence of the harmful effects of high salt intake in the adult population.

Trends in cigarette smoking in 36 populations from the early 1980s to the mid-1990s: findings from the WHO MONICA Project.

OBJECTIVES: This report analyzes cigarette smoking over 10 years in populations in the World Health Organization (WHO) MONICA Project (to monitor trends and determinants of cardiovascular disease). METHODS: Over 300,000 randomly selected subjects aged 25 to 64 years participated in surveys conducted in geographically defined populations. RESULTS: For men, smoking prevalence decreased by more than 5% in 16 of the 36 study populations, remained static in most others, but increased in Beijing. Where prevalence decreased, this was largely due to higher proportions of never smokers in the younger age groups rather than to smokers quitting. Among women, smoking prevalence increased by more than 5% in 6 populations and decreased by more than 5% in 9 populations. For women, smoking tended to increase in populations with low prevalence and decrease in populations with higher prevalence; for men, the reverse pattern was observed. CONCLUSIONS: These data illustrate the evolution of the smoking epidemic in populations and provide the basis for targeted public health interventions to support the WHO priority for tobacco control.

The feasibility of routine mortality and morbidity register data linkage to study the occurrence of acute coronary heart disease events in Finland. The Finnish Cardiovascular Diseases Registers (CVDR) Project.

Validated population-based data on the occurrence of coronary heart disease in Finland have previously been obtained from myocardial infarction (MI) registers. Such registers cannot, however, cover large areas. Therefore, the Finnish Cardiovascular Diseases Registers (CVDR) Project was set up to obtain data for the whole of Finland. The CVDR Project is based on routine mortality and morbidity data linkage. We report here the overall approach used in the project, the results of the feasibility study and the first main results. In Finland, data on all hospitalizations are registered in the nationwide Hospital Discharge Register. Also, data on all deaths are collected in the nationwide Causes of Death Register. The unique personal identification number assigned to all persons residing in Finland was used for data linkage. Data have been validated using the FINMONICA MI registers. Sensitivity analyses showed that the data were robust and consistent between different geographical areas. Coronary heart disease (CHD) mortality as well as the incidence and event rates showed the same very clear geographical pattern, dividing Finland to a southwest area with a lower occurrence and a northeast area with nearly twice higher occurrence. Case fatality did not differ much between the areas and did not follow this Southwest-Northeast division. The differences between northeast and southwest Finland may be related to differences in risk factor levels but also to socioeconomic and genetic differences. The CVDR Project data will be instrumental in further research addressing these issues.

The feasibility of combining data from routine Hospital Discharge and Causes-of-Death Registers for epidemiological studies on stroke.

We assessed the validity of hospital discharge data on stroke in Finland and the feasibility of linked hospital discharge and causes-of-death data for epidemiological studies using the FINMONICA Stroke Register as the reference. The results showed that such data can, with some caution, be used for incidence studies and for identifying first stroke events. They cannot, however, be used for assessing secular trends in all stroke events.

Changes in cigarette smoking among adults in 35 populations in the mid-1980s. WHO MONICA Project.

OBJECTIVE: To examine changes in the prevalence of cigarette smoking in 35 study populations of the World Health Organisation's MONICA Project. DESIGN: Data from two independent, community-based surveys conducted, on average, five years apart. SETTING: Geographically defined populations in 21 countries mainly in eastern and western Europe. SUBJECTS: Randomly selected men and women aged 25-64 years. Numbers of participants in each study population ranged from 586 to 2817 in each survey. MAIN OUTCOME MEASURES: Changes in proportions of current smokers, ex-smokers, and never-smokers by age and sex using data collected by standardised methods. RESULTS: Among men, smoking prevalence decreased in most populations, by three to four percentage points over five years. In Beijing, however, it increased in all age groups--overall by 11 percentage points. Among women there were increases in smoking in about half the populations. The increases were mainly in the age group 35-54 years and often in those populations where smoking prevalence among women has been relatively low. CONCLUSIONS: Smoking initiation by middle-aged women in parts of southern and eastern Europe and among men of all ages in Beijing is a matter of concern. The various public health measures that have helped to reduce smoking among men in developed countries should be vigorously extended to these other groups now at growing risk of smoking-related disease.

Changes in estimated coronary risk in the 1980s: data from 38 populations in the WHO MONICA Project. World Health Organization. Monitoring trends and determinants in cardiovascular diseases.

The World Health Organization (WHO) MONICA Project is a 10-year study monitoring trends and determinants of cardiovascular disease in geographically defined populations. Data were collected from over 100,000 randomly selected participants in two risk factor surveys conducted approximately 5 years apart in 38 populations using standardized protocols. The net effects of changes in the risk factor levels were estimated using risk scores derived from longitudinal studies in the Nordic countries. The prevalence of cigarette smoking decreased among men in most populations, but the trends for women varied. The prevalence of hypertension declined in two-thirds of the populations. Changes in the prevalence of raised total cholesterol were small but highly correlated between the genders (r = 0.8). The prevalence of obesity increased in three-quarters of the populations for men and in more than half of the populations for women. In almost half of the populations there were statistically significant declines in the estimated coronary risk for both men and women, although for Beijing the risk score increased significantly for both genders. The net effect of the changes in the risk factor levels in the 1980s in most of the study populations of the WHO MONICA Project is that the rates of coronary disease are predicted to decline in the 1990s.

Association between salt intake, heart rate and blood pressure.

The present study investigated the association between 24-h urinary sodium excretion and heart rate in the determination of blood pressure (BP) levels in a large random population sample from eastern Finland. Three independent risk factor surveys were performed in 1979, 1982 and 1987 using the same methodology. Data from each survey was pooled for subjects aged 25-64 years who reported a complete 24-h urine collection and were not on the current antihypertensive treatment (1640 men and 1686 women). The effect of urinary sodium excretion and heart rate was examined by regressing BP on urinary sodium excretion and pulse rate, together with age and body mass index (BMI). Analyses stratified by quintiles of heart rate were also performed. There was no association between urinary sodium and BP either in men or in women. There was a significant correlation between heart rate and both systolic and diastolic BP in both men and women. A significant interaction between age and BMI with heart rate was also found in both sexes. Interaction between urinary sodium and heart rate was found neither in men nor in women. Among men, after adjustment for age and BMI, there was a curvilinear relation between 24-h urinary excretion of sodium and diastolic BP (P = 0.054) in the lowest quintile of heart rate (<60 beats/min). No correlations were observed among women in any of the quintiles of heart rate.