Vivan Lundberg

The events registration and survey procedures in the Northern Sweden MONICA Project

Introduction: The WHO MONICA Project (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) was initiated in 1982. The purpose was to evaluate to what extent mortality trends could be explained by changes over time in the population load of conventional cardiovascular risk factors. To test this hypothesis, time trends in cardiovascular event rates have been correlated with trends in levels of risk factors in 35- to 64-year-old men and women in 38 populations. In most MONICA populations, the study has covered a period of 10 years or more. Methods: All acute myocardial infarction and stroke events have been registered in a population-based setting in Norrbotten and Västerbotten counties from 1985 and onwards. The total population is approximately 510,000 inhabitants. In the frame of the WHO MONICA Project, the same strict criteria have been used in all years. Another part of the MONICA Project is population risk factor surveys. In Northern Sweden the first survey took place in 1986 and the following surveys were performed in 1990, 1994, and 1999, including the age group 25 - 74 years (the first two surveys were of the age range 25 - 64 years). Results: From 1985 to 2000, in total 18,105 suspected stroke events, aged 25 - 74 years, were scrutinized and validated at the central stroke office in Northern Sweden. Of these, 13,908 were found to fulfil the MONICA criteria of an acute stroke. During the period 1985 to 1998, in total 13,228 cases of suspected acute myocardial infarction, aged 25 - 64 years, were registered. Of these, 8,744 fulfilled the MONICA criteria for acute myocardial infarction. In the four surveys, in total 9,000 randomly selected men and women were invited for survey. Of these 6,952 (77%) participated in the surveys. Conclusion: From 1985 and onwards, the WHO MONICA project has been going on in Northern Sweden. During the whole time the same strict WHO criteria have been followed.

Smokeless tobacco as a possible risk factor for myocardial infarction: a population-based study in middle-aged men

OBJECTIVES To explore whether the use of snuff affects the risk of myocardial infarction (MI). BACKGROUND Snuff and other forms of smokeless tobacco are widely used in some populations. Possible health hazards associated with the use of smokeless tobacco remain controversial. METHODS In a population-based study within the framework of the Northern Sweden center of the World Health Organization Multinational Monitoring of Trend and Determinants in Cardiovascular Disease (WHO MONICA) Project, tobacco habits were compared in 25- to 64-year-old men with first-time fatal or nonfatal MI and referent subjects matched for age and place of living (687 cases, 687 referents). RESULTS The unadjusted odds ratio (OR) for MI in regular cigarette smokers as compared with men who never used tobacco was 3.65 (95% confidence interval [CI] 2.67 to 4.99). When nonsmoking regular snuff dippers were compared with never-users of tobacco, the unadjusted OR was 0.96 (0.65 to 1.41). After adjustment for multiple cardiovascular risk factors, the OR was 3.53 (95% CI 2.48 to 5.03) for regular smoking and 0.58 (95% CI 0.35 to 0.94) for regular snuff dipping. Restricting the analyses to fatal cases of myocardial (including sudden death) showed a tendency towards increased risk among snuff dippers 1.50 (95% CI 0.45 to 5.03). CONCLUSIONS The risk of MI is not increased in snuff dippers. Nicotine is probably not an important contributor to ischemic heart disease in smokers. A possible small or modest detrimental effect of snuff dipping on the risk for sudden death could not be excluded in this study due to a limited number of fatal cases.

Diabetes as a risk factor for myocardial infarction: population and gender perspectives

Abstract. Lundberg V, Stegmayr B, Asplund K, Eliasson M, Huhtasaari F (Kalix Hospital, Umel University Hospital and Lulei‐Boden Hospital, Sweden). Diabetes as a risk factor for myocardial infarction: population and gender perspectives.

Increased incidence of and impaired prognosis after acute myocardial infarction among patients with seropositive rheumatoid arthritis

Objective: To examine the incidence and outcome of acute myocardial infarction (AMI) in patients with rheumatoid arthritis compared with the general population, and to examine whether care and treatment of an AMI differs between patients and controls. Methods: The Multinational Monitoring of Trends and Determinants of Cardiovascular Disease register for northern Sweden was used to compare those incidences of AMI in a cohort of patients with rheumatoid arthritis with that in the general population. 35 patients with rheumatoid arthritis who had also experienced an AMI were identified. For each patient with rheumatoid arthritis, three controls with a history of AMI but without rheumatoid arthritis were randomly selected from the same register, and matched for age, sex and year of the AMI for evaluation of case fatality and potential differences in treatment of AMI. Results: The standardised incidence ratio for AMI was 2.9 in patients with rheumatoid arthritis compared with the general population (p<0.05). During the first 10 years after an AMI, patients with rheumatoid arthritis had a higher overall case fatality compared with controls (hazard ratio (HR) 1.67, 95% confidence interval (CI) 1.02 to 2.71). Survival time was decreased in the rheumatoid arthritis group compared with controls despite the same care and treatment. Conclusion: Both the incidence of and case fatality after an AMI were higher among patients with rheumatoid arthritis than among the general population. The results emphasise the necessity of optimising the preventive, diagnostic and caring strategies for AMI in rheumatoid arthritis.

Diabetes and obesity in Northern Sweden: occurrence and risk factors for stroke and myocardial infarction

Aims: The authors describe the occurrence of diabetes and obesity in the population of Northern Sweden and the role of diabetes in cardiovascular disease. Methods: Four surveys of the population aged 25 to 64 years were undertaken during a 14-year time span. Stroke events in subjects 35 - 74 years during 1985 - 92 and myocardial infarction in subjects 25 - 64 years 1989 - 93 were registered. Results: The prevalence of diagnosed diabetes was 3.1 and 2.0% in men and women, respectively, and 2.6 and 2.7% for previously undiagnosed diabetes. During the 13-year observation period, BMI increased 0.96 kg/m2 in men and 0.87 in women. The proportion of subjects with obesity (BMI≥30) increased from 10.3% to 14.6% in men and from 12.5% to 15.7% in women. Hip circumference increased substantially more than waist circumference, leading to a decreasing waits-to-hip ratio (WHR). The relative risk for stroke or myocardial infarction was four to six times higher in a person with diabetes than in those without diabetes. The 28-day case fatality for myocardial infarction, but not for stroke, was significantly higher in both men and women with diabetes. Population-attributable risk for diabetes and stroke was 18% in men and 22% in women and for myocardial infarction it was 11% in men and 17% in women. Conclusion: Obesity is becoming more common, although of a more distal than central distribution. The burden of diabetes in cardiovascular diseases in Northern Sweden is high.

Exploring sex differences in case fatality in acute myocardial infarction or coronary death events in the northern Sweden MONICA Project

Abstract. Lundberg V, Wikström B, Boström S, Asplund K (Kalix Hospital and Umeå University Hospital, Sweden). Exploring sex differences in case fatality in acute myocardial infarction or coronary death events in the northern Sweden MONICA Project. J Intern Med 2002; 251: 235–244.

Marked improvement in survival after acute myocardial infarction in middle-aged men but not in women. The Northern Sweden MONICA study 1985-94.

Abstract. Peltonen M, Lundberg V, Huhtasaari F, Asplund K (Umeå University Hospital, Kalix Hospital and Luleå‐Boden Hospital, Sweden). Marked improvement in survival after acute myocardial infarction in middle‐aged men but not in women. The Northern Sweden MONICA study 1985–94. J Intern Med 2000; 247: 579–587.

MONICA quality assessments.

The authors give an overview of the quality assessments in the WHO MONICA project and compare the quality of the data from Northern Sweden with other reporting units. Methods and results: Standardized measurement procedures and routine checks were used to ensure good quality of the data. The quality has been evaluated by a scoring system. The results show that the data from Northern Sweden have good quality for all variables except total cholesterol in the initial survey. In the subsequent surveys, the quality of cholesterol data was good. Conclusions: Great effort was put in to ensure good data quality and Northern Sweden is one of the MONICA units with very good quality of data.

Favourable trends in the incidence and outcome of myocardial infarction in nondiabetic, but not in diabetic, subjects : findings from the MONICA myocardial infarction registry in northern Sweden in 1989-2000

Background:  The aim of this study was to compare time trends in incidence, case fatality and mortality due to myocardial infarction (MI) in patients with or without diabetes.

Secular trends in social patterning of cardiovascular risk factor levels in Sweden. The Northern Sweden MONICA study 1986-1994

Peltonen M, Huhtasaari F, Stegmayr B, Lundberg V, Asplund K (Umeå University Hospital, Luleå‐Boden Hospital, Kalix Hospital, Sweden). Secular trends in social patterning of cardiovascular risk factor levels in Sweden. The North Sweden MONICA Study 1986–1994. J Intern Med 1998; 244: 1–9.