Risk factors associated with body mass index increase in men at 28 years follow-up.

BACKGROUND: Several studies have reported a general increase in body mass index (BMI). AIM: To identify factors influencing BMI changes at 28 years follow-up. DESIGN: Prospective screening study. METHODS: The cohort of the Oslo I study of 1972/73 had another screening in 2000 (Oslo II). We present data for these men, and men from Oslo I who participated in five similar studies during 1996-2001. In all, 7157 men aged 20-49 years at first screening attended two health screenings, and complete data were available for 7104. BMI change from 1972/73 to 2000 was the dependent variable in multiple regression analyses. RESULTS: The percentage with obesity (BMI > or = 30) increased overall from 2.5% to 13.5%. The overall mean (SD) BMI increased from 24.2 (2.6) kg/m2 to 26.2 (3.4) kg/m2. The increase was largest (3.9 (2.5) kg/m2) among men aged 20-24 in 1972/73 and least (1.6 (2.5) kg/m2) in those aged 45-49 years. No age trend was observed for those with BMI > or = 30.0 kg/m2 in 1972/3. On multiple regression analysis, increasing triglycerides, systolic blood pressure, age and non-fasting glucose, decreasing physical activity and not smoking were all significantly related to increasing BMI. Having stopped smoking was also related to increased BMI. Daily smoking in both 1972/73 and 2000, and daily smoking in 2000 but not in 1972/73, were inversely related to increased BMI. DISCUSSION: There was a substantial increase in BMI, with the largest increase in the younger men, except in those who were already obese at first screening. Overall, obesity increased by 11% in the study period and was associated with multiple life-style factors.

Cardiovascular diseases and diabetes mellitus in different ethnic groups: the Finnmark study.

The mortality from coronary and cerebrovascular diseases is higher in Finnmark County than in other Norwegian counties. In a population-based cohort study, we compared the incidence of myocardial infarction, stroke, and diabetes mellitus in different ethnic groups in Finnmark. A total of 10,622 subjects of Norse, Sami, and Finnish origin were followed for 14 years. During approximately 150,000 person-years, we identified 509 and 84 cases of myocardial infarction, 107 and 75 cases of stroke, and 96 and 73 cases of clinical diabetes mellitus among men and women, respectively. A total of 533 men and 199 women died. Norse subjects born outside of Finnmark had the most favorable risk factor levels and, in general, the lowest incidence of disease. Men of Finnish origin had a higher incidence rate of all endpoints than other men, and Finnish women had a higher incidence rate of myocardial infarction than other women. Sami women were more obese but did not have a higher diabetes mellitus incidence than other women. After adjustment for major cardiovascular risk factors and height, most ethnic differences were attenuated.

[Can we rely on self-reported smoking habits?]. / Kan vi stole på egenerklaerte røykevaner?

The reliability of self-reporting on smoking habits has been evaluated by comparing the reported smoking habits with the concentration of serum thiocyanate, which is higher in smokers than in non-smokers and increases with increasing cigarette consumption. When a smoker stops smoking, the level of serum thiocyanate decreases and falls to the level observed in non-smokers after about one month. When the questions asked about smoking were neutral, the reported smoking habits were generally reliable. However, in cases where the questions asked and the interview situation could be regarded as unpleasant, the reported smoking habits were not always correct. Some smokers underreported the number of cigarettes they smoked on a daily basis and some of them denied smoking altogether.

Sex differences in risk factors for clinical diabetes mellitus in a general population: a 12-year follow-up of the Finnmark Study.

The associations among obesity, height, cardiovascular risk factors, and the incidence of clinical diabetes mellitus were investigated in the Norwegian population-based Finnmark Study of 11,654 men and women aged 35-52 years at baseline in 1977-1978. A total of 87 cases of diabetes among men and 75 cases among women were registered during 12 years of follow-up. The incidence of diabetes was 1.1 per 1,000 person-years in women and 1.2 per 1,000 person-years in men, but sex-related differences in risk factors were noted. Body mass index was the dominant risk factor in men and predicted diabetes in a dose-response relation in both sexes. However, in women, the association between body mass index and diabetes was greatly attenuated after multivariable adjustment. Serum lipid concentrations were similar in prediabetic men and women; thus, prediabetic women had a relatively more adverse metabolic risk profile as compared with nondiabetics of the same sex. In multivariable analysis, high density lipoprotein cholesterol was inversely related to diabetes in women (relative risk per 0.3 mmol/liter, 0.53; 95% confidence interval 0.41-0.70) but not in men (relative risk, 0.97; 95% confidence interval 0.78-1.19). Serum glucose was a highly significant predictor in both sexes, while height was inversely related to diabetes only in women (relative risk per 5 cm, 0.71; 95% confidence interval 0.58-0.87).

Serum lipids in postmenopausal or perimenopausal women using estrogen alone, estrogen with levonorgestrel, or estrogen with norethisterone, compared with nonusers: results from a cross-sectional study in two Norwegian counties 1985-1988.

The aim of this study was to compare, in a population setting of postmenopausal or perimenopausal women aged 40 to 54, the levels of serum lipids in women using different hormone replacement therapy (HRT) regimens with women using no sex hormones. There was no unequivocal tendency of a more healthy lifestyle among those using HRT than among nonusers. Any type of regimen was associated with a lower mean level of total and calculated low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol was 0.08 mmol/L (5.2%) higher in those using estrogen alone, 0.07 mmol/L (4.5%) higher in users of HRT with norethisterone, and 0.07 mmol/L (4.5%) lower in users of HRT with levonorgestrel, compared with nonusers. The ratio of total-to-HDL cholesterol was lower by 0.37 (6.1%) in those using estrogen alone, by 0.65 (12.3%) in those using HRT with norethisterone, and by 0.24 (5.3%) in those using estrogen with levonorgestrel. There was no association between body mass index and HDL-cholesterol among women who used HRT with norethisterone, whereas an inverse relationship was present in those using estrogen alone and in nonusers (P [interaction] < 0.05).

Body height, cardiovascular risk factors, and risk of stroke in middle-aged men and women. A 14-year follow-up of the Finnmark Study.

BACKGROUND: Geographical differences in stroke mortality are not fully explained by population variations in blood pressure and antihypertensive treatment. Some studies have suggested that factors connected with health and nutrition in early life may be related to stroke morbidity and mortality. Body height is a sensitive marker for socioeconomic conditions, but results are conflicting as to whether height is associated with stroke. METHODS AND RESULTS: In a population-based study, we investigated stroke incidence in relation to height and classic cardiovascular risk factors. A total of 13,266 men and women 35 to 52 years of age were followed for 14 years, and 241 first events of stroke were registered. Stroke incidence was 36% higher in men. Height was inversely related to stroke in a dose-response manner. Per 5-cm increase in height, the age-adjusted risk of stroke was 25% lower in women (P < .0001) and 18% lower in men (P = .0007). Systolic blood pressure and daily smoking were positively associated with stroke in both sexes, while serum triglyceride level was a significant risk factor in women only (relative risk per 1 mmol/L, 1.3; 95% CI, 1.1 to 1.5). The associations remained after adjustment for possible confounders and were also observed in certain subtypes of stroke. CONCLUSIONS: The results are consistent with the theory that factors influencing early growth as well as adult lifestyle factors contribute to cerebrovascular disease in adult age.

Chronic consumers of boiled coffee have elevated serum levels of lipoprotein(a).

OBJECTIVES: Lipoprotein(a) consists of an LDL-particle attached to apolipoprotein(a), which is made by the liver. Diterpenes present in boiled coffee raise serum levels of LDL cholesterol and of the liver enzyme alanine aminotransferase in man. We investigated the association between intake of boiled coffee and serum levels of lipoprotein(a). DESIGN, SETTING AND SUBJECTS: Healthy Norwegians 40-42 years of age, who habitually consumed five or more cups of boiled coffee per day (n = 150) were compared with matched filter coffee consumers (n = 159) in a cross-sectional study, as part of the Norwegian National Health Screening in 1992. RESULTS: The median lipoprotein(a) level was 13.0 mg dL-1 (10th and 90th percentile: 2.5 and 75.0 mg dL-1, respectively) on boiled and 7.9 mg dL-1 (10th and 90th percentile: 1.9 and 62.5 mg dL-1, respectively) on filter coffee (P = 0.048). Means +/- SE were 25.8 +/- 2.4 mg dL-1 and 19.6 +/- 2.0 mg dL-1, respectively (P = 0.04). Although not statistically significant, subjects consuming nine or more cups of coffee per day had higher lipoprotein(a) levels than those drinking five to eight cups per day in both coffee groups. CONCLUSION: Chronic consumers of unfiltered, boiled coffee have higher serum levels of lipoprotein(a) than filter coffee drinkers.

Smoking, serum lipids, blood pressure, and sex differences in myocardial infarction. A 12-year follow-up of the Finnmark Study.

BACKGROUND: Few epidemiological studies have investigated the relative importance of major coronary risk factors in the two sexes within the same study population. In particular, it is not clear whether smoking carries a similar risk of coronary heart disease in men and women. METHODS AND RESULTS: The associations between smoking, serum lipids, blood pressure, and myocardial infarction were examined in a population-based prospective study of 11,843 men and women aged 35 to 52 years at entry. During 12 years, 495 cases of first myocardial infarction among men and 103 cases among women were identified. Myocardial infarction incidence was 4.6 times higher among men. The incidence was increased sixfold in women and threefold in men who smoked at least 20 cigarettes per day compared with never-smokers, and the rate in female heavy smokers exceeded that of never-smoking men. Multivariate analysis identified current smoking as a stronger risk factor in women (relative risk, 3.3; 95% confidence interval [CI], 2.1 to 5.1) than in men (relative risk, 1.9; 95% CI, 1.6 to 2.3). Among those under 45 years old at entry, the smoking-related sex difference was more pronounced (in women: relative risk, 7.1; 95% CI, 2.6 to 19.1) (in men: relative risk, 2.3; 95% CI, 1.6 to 3.2). Serum total cholesterol, HDL cholesterol, and systolic blood pressure were also highly significant predictors in both sexes. CONCLUSIONS: Smoking was a stronger risk factor for myocardial infarction in middle-aged women than in men. Relative risks associated with serum lipids and blood pressure were similar despite large sex differences in myocardial infarction incidence rates.

Asbestos-related radiographic changes by ILO classification of 10 x 10 cm chest X-rays in a screening of the general population.

A sample of 1388 10 x 10 cm chest X-rays from a previous population screening of males aged 40+ years were reevaluated by use of the ILO classification. There were 1036 films of subjects from an industrialized town, and 352 from a rural community. The observed rates of parenchymal changes (profusion > or = 1/0) at the reevaluation were 1.3% in the urban community and 3.4% in the rural community. The corresponding figures for pleural changes were 5.0% and 0.6%, respectively. Based on additional questionnaire information on asbestos exposure, it was found that the radiographic changes were probably related to past asbestos exposure for 2.3% of the subjects from the urban community and 0.6% from the rural community. In cases of asbestos-related illnesses the mean time since first exposure to asbestos was 35.9 years, whereas the mean duration of the exposures was 11.4 years. The results seem to indicate that the ILO reassessment of the radiographs was more sensitive in detecting pleural changes than the previous clinical screening of both small and large films.

[Is blood pressure treatment as effective in a population setting as in controlled studies?]. / Er blodtrykksbehandling like effektivt i befolkningen som i kontrollerte forsøk?

Baseline (1974-76) and repeat (1977-81) cardiovascular screenings of 21,314 men aged 35-49 years brought to light 840 men who had started treatment between screenings. These were compared with men who had remained untreated. The effects of treatment on blood pressure were small, and normal target blood pressures rare. At pretreatment blood pressure up to systolic 184 mm Hg, and in most risk strata, both total mortality and cardiovascular mortality were higher among the men on treatment. This study shows an adverse effect of treatment in a population setting, particularly at low pretreatment blood pressure, and if blood pressure increases upon treatment.

Is blood pressure treatment as effective in a population setting as in controlled trials? Results from a prospective study.

OBJECTIVE: To evaluate the effectiveness of treatment in situations in which general practitioners and patients use medication according to their own judgement, and where selection, compliance and follow-up varies. This prospective population study differs from the efficacy of treatment studied in randomized trials. DESIGN: Baseline (1974-1976) and repeat (1977-1981) cardiovascular screenings of all males aged 35-49 years in three counties in Norway, with mortality follow-up from the second screening until 1990. SETTING: A nationwide ambulatory screening service reporting community results and referring high-risk subjects to their local general practitioners. PARTICIPANTS: A total of 21,314 males (86%) attended both screenings, of whom 840 took blood pressure medication at the second screening. Males with cardiovascular disease, diabetes or blood pressure treatment at baseline were excluded. MAIN OUTCOME MEASURES: Changes in coronary risk factors, mortality from all causes, coronary heart disease and non-cardiovascular causes. RESULTS: The effect of treatment on blood pressure was small, and the attainment of reasonable target blood pressures was rare. The cholesterol level decreased and the level of triglycerides increased more in the treatment group than in the untreated group. Blood pressure treatment was associated with increased mortality in most risk strata, and at pretreatment systolic blood pressures up to 184 mmHg. A particularly high mortality rate was found when blood pressure increased despite treatment and at low pretreatment blood pressures. According to Cox proportional hazards analyses controlling for pretreatment blood pressure, cholesterol, age, smoking and body mass index, the relative risk of coronary heart disease death in the treatment group was 1.8 (95% confidence interval 1.3-2.6). CONCLUSION: The benefit experienced from the trials turned into an adverse effect of treatment in the population setting, particularly at low pretreatment blood pressure, and when blood pressure increased during treatment.

Identity of the cholesterol-raising factor from boiled coffee and its effects on liver function enzymes.

Boiled coffee contains an unidentified lipid that raises serum cholesterol. We studied the effects of the ingestion of coffee oil fractions of increasing purity in volunteers in order to identify the cholesterol-raising factor. In 15 volunteers who ingested 0.75 g/d of a non-triglyceride-fraction from coffee oil for 4 weeks, mean cholesterol increased by 48 mg/dl (1.2 mmol/l) relative to placebo. In contrast, a coffee oil stripped of the non-triglyceride lipids cafestol and kahweol had no effect. In three volunteers, purified cafestol (73 mg/d) plus kahweol (58 mg/d) increased cholesterol by 66 mg/dl (1.7 mmol/l) after 6 weeks. Oil from Robusta beans, which contains cafestol but negligible kahweol, also raised serum cholesterol. These findings show that cafestol is at least partly responsible for the cholesterol-raising effect of boiled coffee. Coffee oils and brews containing cafestol consistently increased serum triglycerides and alanine amino-transferase, and depressed serum creatinine and gamma-glutamyl-transferase (GGT). After withdrawal GGT activity rose above baseline. Norwegians who habitually consumed 5-9 cups of boiled coffee per day had higher serum cholesterol levels and lower GGT but no higher alanine aminotransferase activity than controls. Thus, serum cholesterol is raised by cafestol and possibly also kahweol, both natural components of coffee beans. The mechanism of action is unknown but is accompanied by alterations in liver function enzymes.

Age-specific genetic effects for blood pressure.

Correlations between relatives were determined for systolic and diastolic blood pressure. The correlations decrease as age differences between relatives increase in a Norwegian sample with 43,751 parent-offspring pairs, 19,140 pairs of siblings, and 169 pairs of twins. A simple biometric model specifying only age-specific genetic additive effects and environmental effects fitted well to correlations between cotwins, pairs of siblings, and parent-offspring dyads in subsets of relatives grouped by age differences. None of the environmental effects appeared to be due to environmental factors that are shared by family members. Models that excluded a parameter for the age-specific genetic influence did not fit the data. The results may partly explain what seems to be a discrepancy between relatively low parent-offspring correlations from previous nuclear family studies and high correlations from twin studies, especially in identical twins.

[Social network, alcohol drinking habits and injuries caused by violence among women and men in the county of Akershus. Results from anonymous questionnaires among persons aged 40-42 years. 1990-91]. / Sosialt nettverk, alkoholvaner og voldsskader hos kvinner og menn i Akershus fylke. Resultater fra anonym spørreundersøokelse blant 40-42-åringer 1990-91.

All residents aged 40-42 in Akershus county were invited to screening for cardiovascular risk factors in 1990-91 as part of a prevention programme. Of the 13,607 attendants, 8,960 answered an anonymous questionnaire about social network, drinking habits, and injuries due to violence. Compared with data from the Central Bureau of Statistics, our material included a high percentage of persons with a higher education, a high percentage of married persons, and a low percentage of persons living alone. Results in respect of social network and drinking habits roughly agreed with those of other studies. Of the males, 15.7% had been injured at least once as a result of violence, most often assault and robbery. Of the females, the corresponding percentage was 18.1. Here the dominating forms of violence were maltreatment, threats and sexual assault. Females were more often exposed than males to repeated violence and more often suffered persisting problems as a result of maltreatment. Compared with other studies, we found a high prevalence of injuries from violence among females, suggesting underreporting of experiences of violence by females in studies based on personal interview or the hospitals' injury register.

High-density lipoprotein cholesterol and coronary, cardiovascular and all cause mortality among middle-aged Norwegian men and women.

From 1977 to 1982 screening for cardiovascular disease was performed in three Norwegian counties. All those aged between 40 and 54 years were invited, of whom 23,690 men and 23,425 women (90%) attended. Smoking habits and previous cardiovascular disease were recorded; total cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), triglycerides and blood pressure were measured. During subsequent follow-up (mean 6.8 years) 422 men and 54 women died from coronary heart disease, 514 and 114 from all cardiovascular diseases and 983 and 404 from all causes, men and women respectively. For men, mortality decreased with increasing HDL cholesterol, to a minimum of around 1.5 mmol.l-1 (58 mg.dl-1), whereafter mortality increased. This applies to coronary, cardiovascular and all causes of death, as well as to men with and without a history of disease. The association between mortality and HDL cholesterol in healthy men disappeared when total cholesterol was below 6.5 mmol.l-1 (251 mg.dl-1). The inverse association between mortality and HDL cholesterol in women was somewhat stronger than in men, both for coronary and cardiovascular diseases. The relative risks of coronary death, associated with an increase in HDL cholesterol of 0.5 mmol.l-1 (19 mg.dl-1), from the Cox proportional hazards regression, with other major cardiovascular risk factors as covariates, were 0.8 (95% confidence interval: 0.6, 1.0) and 0.8 (0.7, 1.0) for men with and without history of disease, respectively. Corresponding figures for women were 0.5 (0.3, 0.9) and 0.7 (0.4, 1.3).

Genetic and environmental contributions to the variance of body height in a sample of first and second degree relatives.

Height was measured in a health screening of the population in Nord-Trøndelag, Norway. Correlations were computed for 24,281 pairs of spouses, 43,613 pairs of parents and offspring, 19,168 pairs of siblings, 1,318 pairs of grandparents and grandchildren, 1,218 cognate avuncular pairs, 849 noncognate avuncular pairs, 175 pairs of same-sexed twins, and smaller groups of other types of relatives. Fitting of structural equation models showed proportions of additive genetic variance of approximately 0.8 for both sexes and small sex-specific effects that probably reflect genetic dominance or environmental sibling effects. The correlations between parents and offspring were significantly lower in old than young cohorts, seeming to imply some kind of interaction effect between genes and environment.

[Cardiovascular screenings in Norwegian counties. Background and implementation. Status of risk pattern during the period 1986-90 among persons aged 40-42 years in 14 counties]. / Hjerte- og karundersøkelser i norske fylker. Bakgrunn og gjennomføring. Status 1986-90 for risikomønster blant 40-42-åringer i 14 fylker.

Screening for cardiovascular disease risk factors was carried out in 14 of Norway's 19 counties in 1986-1990 as part of a prevention programme. All residents aged 40-42 were invited. The attendance was 73.5% for males and 82.6% for females. A total of 87,761 persons were examined. The screening included determination of serum cholesterol and triglycerides, measurement of blood pressure, height and weight, and filling in a questionnaire. Mean serum cholesterol was 5.90 mmol/l for males and 5.55 mmol/l for females, mean systolic blood pressure 135.3 and 126.1 mm, and prevalence of daily smoking 43.5 and 41.8%. The risk factor levels in the 341 municipalities of the 14 counties are shown cartographically. For both sexes, the highest risk score was found in the northernmost county, the lowest in southern counties. The risk was also relatively high in some rural areas in southern Norway. By geographical area there was a strong correlation between the risk factor levels of the two sexes, and a less consistent but marked correlation between the means for the various risk factors.

[Cardiovascular screenings in Norwegian counties. Trends in risk pattern during the period 1985-90 among persons aged 40-42 in 4 counties]. / Hjerte- og karundersøkelser i norske fylker. Utvikling 1985-90 av risikomønster blant 40-42-åringer i fire fylker.

In 1985-90, two screenings for cardiovascular disease risk factors were carried out with an interval of three years in four Norwegian counties. All residents aged 40-42 were invited to both screening rounds, and certain subgroups from the first round were re-invited to the second round. Compared with the score attained by the first generation, the total mean risk score for myocardial infarction achieved by the second generation was 19% lower in males, and 15.5% lower in females. The main cause of this reduction was lower serum cholesterol level. Based on results from the subgroups, the estimated mean risk score for the total male cohort from the first round had decreased by 10% at the rescreening three years later. It is concluded that the results indicate a continued, and perhaps accelerated, decrease in coronary heart disease mortality, as new generations populate the age groups where this disease is more prevalent. The screenings were part of a prevention programme, and it is reasonable to assume that the efforts by the primary health care services contributed to the improvement.

Reliability of the Reflotron in the determination of cholesterol.

Measurements of total cholesterol in the field by means of the Reflotron dry-chemistry system (capillary blood) were compared to total cholesterol obtained by a standardized conventional wet-chemistry method in a clinico-chemical laboratory (serum). A total of 1200 people participated in the study. Two identical Reflotron machines were used. In the first period of the study an excellent agreement was found between Reflotron measurements of a reference serum provided by the manufacturer (mean, 4.99 mmol/l; CV, 1.8%) and the stated value (4.97 mmol/l). In the rest of the study higher values and greater variation were found with the Reflotron (mean, 5.32 mmol/l; CV 5.2%). Clearly the Reflotron measurements in the latter period of study were not reliable. In the period with stable instruments most of the values obtained at the two Reflotron machines differed from each other by less than 10%, with a mean difference of 0.08 mmol/l. Reflotron (both machines) and wet-chemistry measurements agreed well for the first 500 participants in the study (mean difference, Reflotron-wet-chemistry, -0.008 mmol/l; 95% confidence interval, -0.035 to 0.019 mmol/l; correlation, 0.967). In this period most Reflotron values differed from wet-chemistry values by less than 9% below to 9% above. With the next 200 participants the Reflotron gave on average slightly higher values than wet-chemistry measurements. The coefficients of variation for measurement variation were higher for Reflotron that for wet-chemistry even in the period with stable instruments. In all parts of the study period a lower HDL-cholesterol level was associated with larger differences between total cholesterol determined by Reflotron and wet-chemistry.

Treatment of hypertension as a risk factor in a prospective study.

The association between blood pressure treatment, blood pressure level and mortality, taking other cardiovascular risk factors into account was studied. A 12-year follow-up of a cardiovascular risk factor screening performed by the Oslo study group in Oslo and by ambulatory teams from the National Health Screening Survey in three counties in Norway was done. All men in Oslo and all men and women in the three counties, (age 40-49) participated, of these 33154 men and 16407 women have complete data on blood pressure and treatment, including subjects reporting previous myocardial infarction or stroke. Mortality from coronary heart disease, stroke and all causes by blood pressure treatment and blood pressure level were studied. At the initial screening 1058 men and 817 women reported taking blood pressure medication, of which 201 and 41 died during follow-up. Total number of deaths were 2341 in men and 421 in women, of these 131 deaths in men and 47 in women reporting previous infarction or stroke. Those reporting blood pressure treatment had a marked excess mortality from cardiovascular disease and all causes of death. A J-shaped association between blood pressure and mortality was marked in the treated group, but weak in those not on treatment. It is concluded that blood pressure treatment is associated with excess mortality from all causes. This may indicate that "real life" treatment outcomes are inferior to those reported from controlled clinical trials. There is a J-shaped association between all cause mortality and blood pressure in men on treatment.