Carotid plaque area and intima-media thickness in prediction of first-ever ischemic stroke: A 10-year follow-up of 6584 men and women: The Tromsø Study

Background and Purpose—Carotid plaque and intima-media thickness (IMT) are recognized as risk factors for ischemic stroke, but their predictive value has been debated and varies between studies. The purpose of this longitudinal population-based study was to assess the risk of ischemic stroke associated with plaque area and IMT in the carotid artery. Methods—IMT and total plaque area in the right carotid artery were measured with ultrasound in 3240 men and 3344 women aged 25 to 84 years who participated in a population health study in 1994 to 1995. First-ever ischemic strokes were identified through linkage to hospital and national diagnosis registries, with follow-up until December 31, 2005. Results—Incident ischemic strokes occurred in 7.3% (n=235) of men and 4.8% (n=162) of women. The hazard ratio for 1 SD increase in square-root-transformed plaque area was 1.23 (95% CI, 1.09–1.38; P=0.0009) in men and 1.19 (95% CI, 1.01–1.41; P=0.04) in women when adjusted for other cardiovascular risk factors. The multivariable-adjusted hazard ratio in the highest quartile of plaque area versus no plaque was 1.73 (95% CI, 1.19–2.52; P=0.004) in men and 1.62 (95% CI, 1.04–2.53; P=0.03) in women. The multivariable-adjusted hazard ratio for 1 SD increase in IMT was 1.08 (95% CI, 0.95–1.22; P=0.2) in men and 1.24 (95% CI, 1.05–1.48; P=0.01) in women. There were no differences in stroke risk across quartiles of IMT in multivariable analysis. Conclusions—In the present study, total plaque area appears to be a stronger predictor than IMT for first-ever ischemic stroke

Seasonal variation in incidence of acute myocardial infarction in a sub-Arctic population: the Tromsø Study 1974-2004

Background: A seasonal pattern with higher winter morbidity and mortality has been reported for acute myocardial infarction (MI). The magnitude of the difference between peak and nadir season has been associated with latitude, but results are inconsistent. Studies of seasonal variation of MI in population-based cohorts, based on adjudicated MI cases, are few. We investigated the monthly and seasonal variation in first-ever nonfatal and fatal MI in the population of Tromsø in northern Norway, a region with a harsh climate and extreme seasonal variation in daylight exposure. Design: Prospective population-based cohort study. Methods: A total of 37 392 participants from the Tromsø Study enrolled between 1974 and 2001 were followed throughout 2004. Each incident case of MI was validated by the review of medical records and death certificates. MI incidence rates for months and seasons were analyzed for seasonal patterns with Poisson regression and the Cosinor procedure. All analyses were stratified by sex, age and smoking status. Results: A total of 1893 first-ever MIs were registered, of which 592 were fatal. There was an 11 % (95% confidence interval: 1.00–1.23, P = 0.04) increased risk of incident MI during winter (November-January) compared with nonwinter seasons, with no statistically significant interaction with sex, age, smoking or calendar year. Other seasonal modelling gave similar but not statistically significant results. Conclusion: We found a small increase in risk of incident MI during the darkest winter months. Populations living in sub-Arctic areas may be adapted to face climate exposure during winter through behavioural protection

Age and gender differences in incidence and case fatality trends for myocardial infarction: A 30-year follow-up. The Tromsø Study

Background: Although the mortality of coronary heart disease (CHD) has declined in Western countries during the last decades, studies have suggested that the prevention and treatment of CHD may not have been as effective in women as in men. We examined gender- and age-specific trends in incidence, case fatality and the severity of first myocardial infarction (MI) in a large Norwegian population-based study. Design: Prospective population-based cohort study. Methods: A total of 31,323 participants enrolled between 1974 and 2001 were followed throughout 2004 for a total of 400,572 person-years. Suspected coronary events were adjudicated by a review of hospital records and death certificates. A total of 1669 events fulfilled standardized criteria of first-ever fatal or non-fatal MI. Results: In the age group 35–79 years, the age-adjusted incidence of MI declined significantly in men, whereas an increase was observed in women. For men and women ≥80 years the incidence rates remained unchanged. The severity of MI and the 28-day and 1-year case fatality rates declined significantly and similarly in men and women. Conclusion: Trends in MI incidence differed by sex and age; in the age group 35–79 years a marked decrease was observed among men but an increase was observed among women, while no change was observed among older patients. MI severity and case fatality were clearly reduced for both sexes. These data suggest that the burden of CHD is shifting from middle-aged men toward middle-aged women and elderly patients

Age and gender differences in incidence and case fatality trends for myocardial infarction: a 30-year follow-up. The Tromsø Study

Background: Although the mortality of coronary heart disease (CHD) has declined in Western countries during the last decades, studies have suggested that the prevention and treatment of CHD may not have been as effective in women as in men. We examined gender- and age-specific trends in incidence, case fatality and the severity of first myocardial infarction (MI) in a large Norwegian population-based study. Design: Prospective population-based cohort study. Methods: A total of 31,323 participants enrolled between 1974 and 2001 were followed throughout 2004 for a total of 400,572 person-years. Suspected coronary events were adjudicated by a review of hospital records and death certificates. A total of 1669 events fulfilled standardized criteria of first-ever fatal or non-fatal MI. Results: In the age group 35–79 years, the age-adjusted incidence of MI declined significantly in men, whereas an increase was observed in women. For men and women ≥80 years the incidence rates remained unchanged. The severity of MI and the 28-day and 1-year case fatality rates declined significantly and similarly in men and women. Conclusion: Trends in MI incidence differed by sex and age; in the age group 35–79 years a marked decrease was observed among men but an increase was observed among women, while no change was observed among older patients. MI severity and case fatality were clearly reduced for both sexes. These data suggest that the burden of CHD is shifting from middle-aged men toward middle-aged women and elderly patients

Longitudinal and secular trends in blood pressure among women and men in birth cohorts born between 1905 and 1977: The Tromso Study 1979 to 2008

High blood pressure is a modifiable risk factor for cardiovascular disease. Previous studies showing a blood pressure decline in recent decades lack data to follow individuals born in different decades from early and middle adulthood to older age. We investigated changes in age-specific blood pressure by repeated measurements in 37973 women and men born 1905 to 1977 (aged 20–89 years) examined ≤ 5× between 1979 and 2008 in the population-based Tromsø Study. Mixed models were used to estimate time trends. Mean systolic and diastolic blood pressure decreased from 1979 to 2008 in both genders in the age groups 30 to 89 years. The decrease was similar in the 80th percentile and the 20th percentile of the population blood pressure distribution. The decrease in systolic blood pressure in age group 40 to 49 years was 10.6 mm Hg in women and 4.5 mm Hg in men. Systolic blood pressure increased with age in women and men born 1920 to 1949, whereas a decrease or flattening of curve was observed in the younger birth cohorts. Thus, we found both time periodic and cohort effects, and trends were more pronounced in women than in men. The findings suggest changes in blood pressure in the population rather than an effect of treatment of high-risk individuals