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M Karvonen

Publications and source records attributed to M Karvonen.

At least 37 records · Page 2Linked to original sources

Comparison of the seasonal pattern in the clinical onset of IDDM in Finland and Sardinia.

OBJECTIVE: To examine the seasonal pattern for the clinical onset of IDDM in Finland and Sardinia, two areas where the incidence of IDDM is the highest in the world, and to determine the effect of climate and temperature on the clinical onset of IDDM. RESEARCH DESIGN AND METHODS: Analysis of seasonality for the diagnosis of IDDM was based on 1,405 cases in Finland and 425 cases in Sardinia diagnosed at < or = 14 years of age from 1989 to 1992. The average annual incidence of IDDM was 36.4/100,000 in Finland and 34.4/100,000 in Sardinia. Seasonal patterns were estimated presenting the data as short Fourier series up to three harmonics together with a possible linear trend. Likelihood ratio tests and Akaike's information criterion were used to determine the number of harmonics necessary to model the seasonal pattern. Seasonal patterns in both countries were compared between sexes and between the three 5-year age-groups, each controlling for the other's effect. RESULTS: In both countries, a significant seasonal pattern during a calendar year was found for the sexes combined and for two age-groups (0-9 and 10-14 years). In Sardinia, two distinct cycles were found in the younger age-group, with a decreased incidence during May through August and an increased incidence during the autumn months. Two cycles were apparent in the older age-group, with the nadir occurring during June through September. In Finland, one cycle was found in the younger age-group, with a decreased incidence in June. In the older age-group, there were two distinct cycles, with a decreased incidence in June and in the September through December period. CONCLUSIONS: Differences between Finland and Sardinia in the seasonal pattern for the incidence of newly diagnosed IDDM cannot be explained by differences in climate, temperature, a longer warm period in Sardinia, or other climatic phenomena. The results do not provide evidence in favor of a specific viral etiology of IDDM. It may be suggested that there are triggering events at certain times, but they are likely to be unspecific. Nevertheless, why the incidence of IDDM in these two populations is equally high despite differences in climate, environment, and genetic background remains an unsolved question.

Adolescent↗

Incidence trends in childhood onset IDDM in four countries around the Baltic sea during 1983-1992.

We present secular trends of childhood onset insulin-dependent diabetes mellitus (IDDM) in Finland, Estonia, Latvia and Lithuania during the period of 1983-1992. Incidence data were obtained from the national IDDM registries. The average age-standardized incidence per 100,000/year was 35.0 in Finland, followed by 10.2 in Estonia, 7.1 in Lithuania and 6.5 in Latvia. A male excess in incidence was recorded in Finland (1.15) and Latvia (1.01). In all countries, the highest age-specific risk of IDDM was observed in the 11-13 year age range. The large difference in incidence between Finland and other Baltic countries was see even in 1-2 year-old children. During the 10-year study period overall changes in incidence of IDDM were relatively small in these four countries. The incidence increased in Finland and Lithuania on average by 1% and 1.4% per year, respectively. A statistically significant increase was recorded only in 0-4 year old children in Finland, at 5.6% per year. In Estonia, an 8.3% increase in this age group, however, was not statistically significant. The different trends in the age-group specific incidence rates were confirmed in Finland. In conclusion, from 1983 to 1992 the incidence of childhood onset IDDM was increasingly in Finland and Lithuania, while in Latvia and Estonia it was stable. There are still great differences in IDDM incidence between the countries around the Baltic Sea.

Adolescent↗

The inverse relation of average population blood pressure and stroke mortality rates in the seven countries study: a paradox.

This study attempts to explain the unexpected finding of an inverse population (ecological) relationship between mean systolic blood pressure levels and stroke death rates in 25 years follow-up of the Seven Countries Study, a cross-cultural study of cardiovascular disease. Sixteen cohorts of all men aged 40-59 in seven countries (one cohort in the USA, two in Finland, one in the Netherlands, three in Italy, two in Croatia (former Yugoslavia), three in Serbia (former Yugoslavia), two in Greece, two in Japan) were surveyed from 1958 to 1964. Risk factors and personal characteristics were measured and follow-up for vital status and cause of death was then carried out over 25 years. Analyses were based on comparisons of mean levels of risk factors and death rates within and among the 16 cohorts. Mean entry population levels of systolic blood pressure among the cohorts were strongly and inversely related with their 25-year stroke death rates (R -0.55; CI -0.81 and -0.06; p = 0.0276). Within cohorts in contrast, the individual relation of blood pressure and stroke was strongly positive and significant in 14 of the 16 cohorts. Mean population levels of serum cholesterol were inversely and strongly related to stroke death rates (R -0.79; CI -0.92 and -0.46; p = 0.0003), while the partial correlation coefficient of systolic blood pressure, computed in models including serum cholesterol, became small and not significant (-0.05; CI -0.55 and +0.48; p = 0.8537). Age at death for stroke (average 68.9 +/- 7.1 years) was significantly higher than age at dath from myocardial infarction and sudden death (average 65.8 +/- 7.8 years) suggesting a competition effect between the conditions. Multivariate models including population average systolic blood pressure and serum cholesterol provided no added explanation for the lack of direct and significant relationship of population blood pressure with stroke death rates. They were based on these variables: age at stroke death, age at myocardial infarction death or and sudden death, death rates from myocardial infarction and sudden death, the interaction term of systolic blood pressure with serum cholesterol and the multivariate coefficients for systolic blood pressure from Cox models run in individuals. Similar findings were obtained using diastolic instead of systolic blood pressure and excluding the Japanese cohorts. The paradox of the inverse ecologic relation of population blood pressure and stroke mortality and a direct relation for individual is only partly explained by the cofounding effect of population mean serum cholesterol levels. An effect of low cholesterol levels on excess stroke mortality cannot be excluded. A major limitation of the study was our inability to segregate thrombotic from heamorrhagic strokes.

Adult↗

Regional differences in the incidence of insulin-dependent diabetes mellitus among children in Finland from 1987 to 1991. Childhood Diabetes in Finland (DiMe) Study Group.

The regional pattern of insulin-dependent diabetes mellitus (IDDM) incidence among children in Finland was analysed applying several methods attempting to describe the geographical variation in occurrence of IDDM. From 1987 to 1991 the number of newly diagnosed cases aged 14 years or less at diagnosis was 1728. The incidence, the incidence rate ratio and the Bayes relative risk (RR) for IDDM were calculated by municipality, by functional area (an urban centre with a subordinated surrounding area) and by area with a population of equal size at risk employing the Geographical Information Systems. The association of IDDM incidence with the degree of urbanization was assessed using the population density as a criterion for the degree of urbanization. The overall mean of the IDDM incidence was 35 per 100000 persons per year. Between municipalities the incidence varied from 4 to 245 per 100000 persons per year, whereas a clear regional pattern was seen among the functional areas and the incidence varied from 26 to 43 per 100000 persons per year. The RR for IDDM among the municipalities ranged from 0.82 to 1.34 and from 0.73 to 1.27 among the functional areas. The incidence determined in four zones with the same size of population was the highest in the middle part of the country. There was a strong inverse correlation between population density and the incidence of IDDM and this also applied to the relationship between child population density and incidence.

Adolescent↗

Detection of overall space-time clustering in a non-uniformly distributed population. DiMe Study Group.

We developed a test statistic based on an approach of Whittemore et al. (1987) to detect space-time clustering for non-infectious diseases. We extended the spatial test of Whittemore et al. by deriving conditional probabilities for Poisson distributed random variables. To combine spatial and time distances we defined a distance matrix D, where dij is the distance between the ith and jth cell in a three-dimensional space-time grid. Spatial and temporal components are controlled by a weight. By altering the weight, both marginal tests and the intermediate test can be reached. Allowing a continuum from a pure spatial to a pure temporal test, the best result will be gained by trying different weights, because the occurrence of a disease might show some temporal and some spatial tendency to cluster. We examined the behaviour of the test statistic by simulating different distributions for cases and the population. The test was applied to the incidence data of insulin-dependent diabetes mellitus in Finland. This test could be used in the analysis of data which are localized according to map co-ordinates, by addresses or postcodes. This information is important when using the Geographical Information System (GIS) technology to compute the pairwise distances needed for the proposed test.

Child↗

Seasonality in the clinical onset of insulin-dependent diabetes mellitus in Finnish children. Childhood Diabetes in Finland (DiMe) Study Group.

Seasonal patterns in the incidence of insulin-dependent diabetes based on 2,062 cases diagnosed at age 14 years or under in Finland are described for the years 1987-1992. Seasonal patterns were estimated presenting the data as short Fourier series up to three harmonics together with a possible linear trend. This method allows an arbitrary shape for the seasonal effect. Likelihood ratio tests and Akaike's information criterion were used to determine the number of harmonics necessary to model the seasonal pattern and to test differences among age- and sex-specific subgroups in the population. Seasonal patterns in incidence were compared between sexes and between the three 5-year age groups with each controlling for the other's effect. A significant seasonal pattern in the incidence of insulin-dependent diabetes was found for the sexes combined and for two age groups (0-9 and 10-14 years). A statistically significant seasonal pattern could be confirmed for males, but not for females. During a calendar year, one cycle with a decreased incidence of insulin-dependent diabetes in June was found among younger boys. Among older boys, there were two distinct cycles with a decreased incidence, the first in June and the second during November-December. The most visible seasonal pattern was a lower number of cases diagnosed in June, while during the rest of the year the incidence remained relatively stable and high. The average annual incidence was 35.6 per 100,000 persons without any upward peaks.

Adolescent↗

Epidemiology of insulin-dependent diabetes mellitus around the Baltic Sea. The DIABALT Study Group.

Great spatial variation in the incidence of IDDM is found among countries around the Baltic Sea, a relative small area on the global scale. We present recent data on IDDM incidence from countries around the Baltic Sea, monthly variation and time trends in incidence from the early 1980s to the early 1990s. The change in IDDM incidence was calculated from logarithms of incidence using linear regression. The incidence was high in the countries to the north and west from the Baltic Sea, being the highest in Finland (35 per 100,000/year) followed by Sweden (26), Denmark (22) and Norway (21). In the countries on the eastern and southern coast of the Baltic Sea the incidence was markedly lower, in Estonia the incidence (10) was the highest within these countries, though slightly less than one third of that in Finland, while it was in Lithuania 7, Latvia 7 and Poland 6. There was an increasing trend in incidence of IDDM in Finland, Norway and Poland. In Sweden the incidence increased from 1978 to 1984, but since then the trend has been flat. In Estonia, Latvia and Lithuania, no significant change in incidence was seen. The reasons for large differences observed in the incidence of IDDM between countries around the Baltic Sea area are unknown, but a complex interaction between genetic and environmental risk factors that can vary in different ethnic, socio-economic and cultural settings play an important role in this variation.

Adolescent↗

Comparison of multivariate predictive power of major risk factors for coronary heart diseases in different countries: results from eight nations of the Seven Countries Study, 25-year follow-up.

BACKGROUND: It was hypothesized that among eight national groups of men aged 40-59 years enrolled in the Seven Countries Study, the multivariate coefficients of major risk factors predicting coronary heart disease mortality over 25 years would be relatively similar. MATERIALS AND METHODS: Sixteen cohorts were located in eight nations and pooled, comprising one cohort in the USA, two in Finland, one in the Netherlands, three in Italy, two in Croatia (former Yugoslavia), three in Serbia (Yugoslavia), two in Greece and two in Japan, for a total of over 12000 subjects at entry. Coronary heart disease (CHD) mortality was defined as fatal myocardial infarction or sudden coronary death, and proportional hazard models were solved, for each country, with age, serum cholesterol level, systolic blood pressure and cigarette consumption as covariates. RESULTS: The relationships between risk factors and CHD mortality were statistically significant for all risk factors and for all countries, except for age in Croatia and Japan, cholesterol in Croatia and Japan, systolic blood pressure in Serbia and Greece, and cigarette-smoking in the Netherlands, Croatia, Serbia and Greece. When comparing all pairs of coefficients (28 comparisons for each factor) significant differences were found on four occasions for age, on six occasions for cholesterol, on no occasion for blood pressure and on four occasions for cigarette-smoking. Other tests suggested a substantial homogeneity among multivariate coefficients. Estimates for pooled coefficients were: age, in years, 0.0570 (95% confidence limits 0.0465 and 0.0673); relative risk for 5 years 1.33 (95% confidence limits 1.26 and 1.40); serum cholesterol level in mg/dl, 0.0057 (95% confidence limits 0.0045 and 0.0069); relative risk for 40 mg/dl 1.31 (95% confidence limits 1.20 and 1.31); systolic blood pressure in mmHg, 0.0160, (95% confidence limits 0.0134 and 0.0185), relative risk for 20 mmHg 1.38 (95% confidence limits 1.31 and 1.45); cigarettes per day, 0.0220 (95% confidence limits 0.0170 and 0.0272); relative risk for 10 cigarettes per day 1.25 (95% confidence limits 1.18 and 1.31). CONCLUSIONS: Great similarities were found in the multivariate coefficients of major coronary risk factors to CHD risk derived from population samples varying in CHD frequency.

Adult↗

Increase in incidence of insulin-dependent diabetes mellitus among children in Finland.

BACKGROUND: In Finland, the incidence of insulin-dependent diabetes mellitus (IDDM) in children aged < 15 years is the highest in the world. The aim of this study was to determine the temporal variation in incidence and the age distribution at diagnosis of IDDM. SUBJECTS AND METHODS: Data on incidence of IDDM in Finland nationwide were obtained from two sources: the Central Drug Registry for the years 1965-1986 (6195 IDDM cases) and the prospective IDDM registry for the years 1987-1992 (2062 IDDM cases). The annual incidence rates were calculated per 100,000 population. The increase in incidence from 1965 to 1992 was estimated by fitting the linear regression with the annual incidence data. RESULTS: The overall incidence of IDDM between 1987 and 1992 was 36 per 100,000/year. During 1965-1992 the increase was almost linear. The regression-based change in incidence was 2.8% per year. In the 1970s the increase in incidence was steepest in 5-9 year olds and since the mid-1980s in those < 5 years old at diagnosis. CONCLUSIONS: The incidence of IDDM in Finnish children seems to increase further. During the last decades the increase in incidence has been almost linear with occasional peaks. The age-at-diagnosis of IDDM has been moving towards the younger ages, and differences in incidence between age groups have now almost disappeared among Finnish children aged 1-14 years.

Adolescent↗

Changes in body weight in relation to mortality in 6441 European middle-aged men: the Seven Countries Study.

OBJECTIVES: To study the relation between changes in body weight and subsequent mortality. DESIGN: Prospective follow-up study. SETTING: Population study. SUBJECTS: 6441 men aged 40-59 y at baseline participating in the European cohorts of the Seven Countries Study. The men were divided into groups depending on their weight pattern ascertained from three weight measurements with intervals of 5 years. They were also divided in quartiles according to the degree of weight variability. MAIN OUTCOME MEASURES: All-cause and cause-specific mortality during 15 years following the last weight measurement. Deaths occurring during the first 5 years of follow-up were excluded. RESULTS: Significantly elevated hazard ratios (RR) for death from all causes (RR = 1.3; 95% confidence interval (CI): 1.2-1.5), all cardiovascular diseases (RR = 1.2; 95% CI: 1.0-1.5) and other causes (RR = 1.6; 95% CI: 1.2-2.2) were found for men with a decreasing weight compared with men with a constant weight. A fluctuating weight was associated with an increased risk of all cause mortality (RR = 1.2; 95% CI: 1.0-1.4), coronary heart disease (RR = 1.5; 95% CI: 1.0-1.9) and myocardial infarction (RR = 1.5; 95% CI: 1.0-2.2). The group of men with an increasing body weight also had elevated hazard ratios for dying from coronary heart disease and myocardial infarction, but these were only significant when the total 15-year follow-up was analyzed. The risks of dying from all-causes, cardiovascular disease, cancer and other causes were increased in the upper quartile versus the lower quartile of weight variability. CONCLUSIONS: The results of the present study show that a decreasing and a fluctuating body weight are associated with increased mortality. An average increase of 7 kg body weight was associated with an elevated risk of dying from coronary heart disease and myocardial infarction. Lowest mortality in these middle-aged men was found in those who maintained a constant body weight.

Aging↗

Relation of serum homocysteine and lipoprotein(a) concentrations to atherosclerotic disease in a prospective Finnish population based study.

The relation of serum total homocysteine and lipoprotein(a) (Lp(a)) with the incidence of atherosclerotic disease was investigated among 7424 men and women aged 40-64 years free of atherosclerotic disease at baseline in 1977. During the 9-year follow-up, 134 male and 131 female cases with either myocardial infarction or stroke were identified. For each case a control subject was selected belonging to the same sex and 5-year age group. Serum samples collected in 1977 were stored at -20 degrees C and analyzed in 1991. The mean serum homocysteine concentration of male cases and controls was 9.99 mumol/l and 9.82 mumol/l at baseline and that of female cases and controls 9.58 mumol/l and 9.24 mumol/l, respectively. The median serum Lp(a) concentration of male cases and controls was 73 mg/l and 108 mg/l and that of female cases and controls 113 mg/l and 91 mg/l, respectively. The differences between cases and controls were not statistically significant. There was also no significant association between either homocysteine or Lp(a) and atherosclerotic disease, myocardial infarction or stroke in logistic regression analyses. The odds ratios varied from 1.00 to 1.26 for homocysteine and from 0.81 to 1.06 for Lp(a). The results of this prospective population-based study do not support the hypotheses that serum homocysteine or Lp(a) are risk factors for atherosclerotic disease. The lack of association between serum homocysteine and atherosclerotic disease may be due to the exceptionally low gene frequency predisposing to homocysteinemia in Finland.

Adult↗

Chlamydia pneumoniae IgG antibody prevalence in south-western and eastern Finland in 1982 and 1987.

Chlamydia pneumonia IgG antibody prevalence was examined in a representative sample (2342 subjects) of the population aged 25-59 years in south-western and eastern Finland in 1982 and 1987. Microimmunofluorescence was used to measure IgG antibodies. Prevalence of C. pneumoniae was modelled using the GLIM statistical package assuming that the prevalence had a binomial distribution. The prevalence was assumed to be a function of the year, subjects' gender, age and place of residence. The effect of the year on the prevalence was significant in both regions (P < 0.05 in the south-west and P < 0.001 in the east). In each year the prevalence was higher in the south-west than in the east and it increased between 1982 and 1987 from 55% to 63% in the south-west and from 41% to 59% in the east. The prevalence increased with age, but the age-related antibody pattern was different between sexes. The highest prevalence was found in men aged 49-59 years. The different increase in prevalence with age in the south-western and the eastern parts of the country indicates that the outbreaks of infection were not related. The endemic level of C. pneumoniae infection in the south-west is consistently higher than in the east, or there was an outbreak of C. pneumoniae infection in both the years we examined. Thus it is more likely that the high prevalence in south-western Finland was connected more with the epidemics reported elsewhere in Scandinavia in the same years than with the occurrence of C. pneumoniae infection in eastern Finland.

Adult↗

Importance of smoking for Chlamydia pneumoniae seropositivity.

BACKGROUND: Population-based studies of the association between smoking and Chlamydia pneumoniae seropositivity do not exist. The role of smoking in the association between C. pneumoniae seropositivity and coronary artery disease (CAD) suggested by several studies has been debated. The aim of this study was to determine the relationship between smoking habits and C. pneumoniae IgG antibody titres in a middle-aged population. We also wanted to find out whether the difference in smoking habits between the sexes explains the higher C. pneumoniae antibody prevalence among men compared with women. RESULTS: After controlling for the effect of smoking, the risk of C. pneumoniae seropositivity remained 1.4 times higher in men than in women. In men, the estimated risk for C. pneumoniae seropositivity (titre > or = 1:16) was significant only for smokers (adjusted odds ratio [OR] = 1.4). The adjusted OR for high seropositivity (titre > or = 1:128) was 1.5 for smokers and 1.7 for ex-smokers. The risk for women was similar to that for men. CONCLUSIONS: The results provide evidence of an association between smoking and C. pneumoniae seropositivity in the general population. The higher prevalence of smoking in men does not explain the C. pneumoniae antibody prevalence in men compared with women.

Adult↗

A review of the recent epidemiological data on the worldwide incidence of type 1 (insulin-dependent) diabetes mellitus. World Health Organization DIAMOND Project Group.

Nearly 70 registries from more than 40 countries have collected and published incidence data of childhood Type 1 (insulin-dependent) diabetes mellitus up to the end of the 1980s. The majority of incidence data comes from regions of high incidence i.e. from Europe and North America. All these published data facilitate the descriptive comparison of incidence and variation of the occurrence of Type 1 diabetes roughly throughout the northern hemisphere. The aim of this paper is to review and compare the most recent epidemiology data on the incidence of Type 1 diabetes among children under the age of 15 years. A clear difference in incidence appeared between northern and southern hemisphere with no countries below the equator having an incidence greater than 15.0 per 100,000. In contrast above the equator the disease is common. Between continents the variation in incidence showed that the lowest incidences were found in Asia, followed by Oceania (Australia and New Zealand), South and North America, and the highest rates were in Europe. The incidence varied from 0.6 per 100,000 in Korea and Mexico to 35.3 per 100,000 in Finland showing prominent worldwide variation in incidence of Type 1 diabetes. The largest intracontinental variation in incidence appeared in Europe, varying from the highest in Finland to the lowest (4.6 per 100,000) in northern Greece. The highest incidence in the world was in northern Europe, but within the continent scale there were some striking exceptions from the overall level of incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The epidemic cycle of Chlamydia pneumoniae infection in eastern Finland, 1972-1987.

The epidemic cycle of Chlamydia pneumoniae infection was examined in two areas in eastern Finland over a period of 15 years, 1972-87. The C. pneumoniae IgG antibody prevalence was determined with 5-year intervals in a random sample of the population aged 25-59 years. The total number of sera studied using immunofluorescence was 2387. In 1972 the antibody prevalence was 57% and it increased to 66% in 1977. Over the next 5 years the prevalence decreased to 44% in 1982, but by 1987 it had again increased to 59%. The temporal variation in prevalence was statistically significant (P < 0.001) and similar for both genders. Throughout the observation period the overall prevalence was 7-11% higher in men than in women (P < 0.01). The antibody prevalence increased with age, being the highest among the oldest study subjects of both genders. The periods of high and low prevalence alternated in an epidemic cycle (P < 0.001) of about 10 years.

Adult↗

Incidence of IDDM in Mauritian children and adolescents from 1986 to 1990.

OBJECTIVE: To document the incidence of IDDM in Mauritian children and adolescents 0-19 yr of age from 1986 to 1990. RESEARCH DESIGN AND METHODS: We used a population-based register that used pediatricians, physicians, nutritionists, and general practitioners as a primary source of retrospective case ascertainment. The denominator data were obtained from the Statistics Office of the Ministry of Health (Port Louis, Mauritius). RESULTS: In 1990, 37 newly diagnosed IDDM cases (22 females and 15 males) were identified between 1986 and 1990 among the population < or = 19 yr of age. The average incidence density per year was 1.9/100,000 people and was slightly higher among girls (2.2/100,000) than among boys (1.5/100,000). The average age-standardized incidence density was 2.1/100,000 people (95% confidence interval 1.5-3.0) among children < or = 14 yr of age, 2.5/100,000 people (95% confidence interval 1.5-3.9) among girls, and 1.8/100,000 people (95% confidence interval 1.0-3.0) among boys. The incidence was similarly low in Mauritians of Asian Indian, Chinese, and Creole (predominantly African) origin. CONCLUSIONS: The incidence of IDDM in Mauritian children and adolescents is among the lowest yet reported. This sharply contrasts with the very high risk of NIDDM found among the adult population in this rapidly modernizing country.

Adolescent↗

The prevalence and regional distribution of antibodies against Chlamydia pneumoniae (strain TWAR) in Finland in 1958.

The occurrence of nonavian 'ornithosis' was reported in Scandinavia at the end of the 1950s. In order to find out whether Chlamydia pneumoniae had been present in Finland, we examined the IgG antibody prevalence to C pneumoniae in samples representing the whole rural population of Finland in 1958. The total number of sera studied using micro-immunofluorescence was 2000. Trend-surface analysis was used to examine the regional patterns of antibody prevalence. C pneumoniae antibodies were present throughout the country. The mean antibody prevalence was 56% among adults and 27% among children. Thus the possible role of C pneumoniae in nonavian 'ornithosis' in Finland between 1958 and 1960 cannot be excluded.

Adolescent↗