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M Karvonen

Publications and source records attributed to M Karvonen.

At least 19 recordsLinked to original sources
PubMed2005

A hierarchical Bayesian birth cohort analysis from incomplete registry data: evaluating the trends in the age of onset of insulin-dependent diabetes mellitus (T1DM).

Childhood diabetes is one of the major non-communicable diseases in children under 15 years of age. It requires a life-long insulin treatment and may lead to serious complications. Along with the worldwide increase in the incidence several countries have recently reported a decreasing trend in the age of onset of the disease. The aim of this study is to analyse long-term data on the incidence of the childhood diabetes in Finland from the birth cohorts perspective. The annual incidence data were available for the period 1965--1996 which translates into 1951--1996 birth cohorts. Hence the data consist of completely and partially observed cohorts. Bayesian modelling was employed in the analysis. Several different priors and cohort combinations were tried in order to determine the sensitivity of the results. The cumulative birth cohort incidence of diabetes was determined to have an increasing average annual trend of 2.5 per cent. Although the average birth cohort-specific age of onset was estimated to have decreased slightly over the years of observation, the trend could be a result of random variation.

Adolescent↗
PubMed2004

Electrocardiographic assessment of left ventricular hypertrophy with time-voltage QRS and QRST-wave areas.

The sum of time-voltage QRS areas in the 12-lead electrocardiogram (ECG) has outperformed other 12-lead ECG indices for detection of left ventricular hypertrophy (LVH). We assessed indices of time-voltage QRS and T-wave (QRST) areas from body surface potential mapping (BSPM) for detection of and quantitation of the degree of LVH. We studied 42 patients with echocardiographic LVH (LVH group) and 11 healthy controls (controls). QRST area sums were calculated from 123-lead BSPM and from the 12-lead ECG for comparison. Leadwise discriminant indices and correlation coefficients were used to identify optimal recording locations for QRST area-based LVH assessment. BSPM QRS area sum was greater in the LVH group than in controls (3752 +/- 1259 vs 2278 +/- 627 microV s, respectively; P<0.001) and at 91% specificity showed 74% sensitivity for LVH detection. The 12-lead QRS area sum performed similarly. Taking T-wave areas into account did not improve the results. QRS area sum from two most informative leads (located in the upper and lower right precordium) also separated the LVH group from controls (61.1 +/- 23.5 vs 27.8 +/- 6.5 microV s, respectively; P<0.00001). This 2-lead QRS area sum showed 90% sensitivity with 100% specificity for LVH detection and maintained high correlation to indexed left ventricular mass (r=0.732; P<0.001). In conclusion, the BSPM QRS area sum compared to 12-lead QRS area sum does not substantially improve LVH assessment. The 2-lead QRS area sum may improve ECG QRS area-based LVH assessment.

Body Surface Potential Mapping↗
PubMed2004

Zinc and nitrate in the ground water and the incidence of Type 1 diabetes in Finland.

AIMS: In Finland, the risk of childhood Type 1 diabetes varies geographically. Therefore we investigated the association between spatial variation of Type 1 diabetes and its putative environmental risk factors, zinc and nitrates. METHODS: The association was evaluated using Bayesian modelling and the geo-referenced data on diabetes cases and population. RESULTS: Neither zinc nor nitrate nor the urban/rural status of the area had a significant effect on the variation in incidence of childhood Type 1 diabetes. CONCLUSIONS: The results showed that although there was no significant difference in incidence between rural and urban areas, there was a tendency to increasing risk of Type 1 diabetes with the increasing concentration of NO3 in drinking water. The fact that no significant effect was found may stem from the aggregated data being too crude to detect it.

Adolescent↗
PubMed2004

Geochemistry of ground water and the incidence of acute myocardial infarction in Finland.

STUDY OBJECTIVE: To examine the association of spatial variation in acute myocardial infarction (AMI) incidence and its putative environmental determinants in ground water such as total water hardness, the concentration of calcium, magnesium, fluoride, iron, copper, zinc, nitrate, and aluminium. DESIGN: Small area study using Bayesian modelling and the geo-referenced data aggregated into 10 km x 10 km cells. SETTING: The population data were obtained from Statistics Finland, AMI case data from the National Death Register and the Hospital Discharge Register, and the geochemical data from hydrogeochemical database of Geological Survey of Finland. PARTICIPANTS: A total of 18 946 men aged 35-74 years with the first AMI attack in the years 1983, 1988, and 1993. MAIN RESULTS: One unit (in German degree degrees dH) increment in water hardness decreased the risk of AMI by 1%. Geochemical elements in ground water included in this study did not show a statistically significant effect on the incidence and spatial variation of AMI, even though suggestive findings were detected for fluoride (protective), iron and copper (increasing). CONCLUSIONS: The results of this study with more specific Bayesian statistical analysis confirm findings from earlier observations of the inverse relation between water hardness and coronary heart disease. The role of environmental geochemistry in the geographical variation of the AMI incidence should be studied further in more detail incorporating the individual intake of both food borne and water borne nutrients. Geochemical-spatial analysis provides a basis for the selection of areas suitable for such research.

Adult↗
PubMed2003

The incidence of type 1 diabetes among children in Finland--rural-urban difference.

The aim of the study was to investigate the incidence of type 1 diabetes among children aged 14 years or under according to the level of urbanization of the place of residence of children at the time of diagnosis in Finland during 1987 to 1996. The analysis was carried out using a Bayesian approach and GIS. The incidence was the highest in the rural heartland areas while the increase in incidence was sharpest in urban areas. The level of urbanization seems to explain only a part of the spatial variation in the incidence in Finland. It is possible that some environmental risk factors for type 1 diabetes have been more prevalent in rural heartland areas than in the rest of the country. These factors might have increased in urban environments in Finland particularly during the first half of 1990s.

Adolescent↗
PubMed2002

Further evidence for the rising incidence of childhood Type 1 diabetes in Kuwait.

AIMS: To provide age-gender standardized incidence rate, temporal trend and seasonal variation of Type 1 diabetes in Kuwaiti children aged < or = 14 years. METHODS: Data were prospectively collected over a period of 6 years (1992-1997) according to the DiaMond Project protocol using the capture-recapture method of ascertainment. RESULTS: Data ascertainment varied between 90% and 96%. The incidence rate of Type 1 diabetes was 20.1 per 100,000 children 0-14 years (95% confidence interval (CI) 18.0-22.1); age-standardized incidence rate 20.9 (95% CI 18.8-23.0). The incidence rate among boys, 21.1 per 100,000 (95% CI 18.1-24.1) was slightly higher than that among girls, 19.0 per 100,000 (95% CI 16.1-21.8). The age-standardized incidence rate was 21.9 (95% CI 18.9-24.8) in boys, and 19.9 (95 CI 17.1-22.8) in girls. Incidence rates increased with age in both sexes (boys chi(2) for linear trend = 13.5, P < 0.001; and for girls chi(2) = 27.8, P < 0.0001). There was a significant trend towards increase in overall incidence during the 6-year period (chi(2) = 6.210, P = 0.013), and in age group 5-9 (chi(2) = 10.8, P = 0.001). Seasonality was demonstrated overall, in boys and girls (P < 0.001). CONCLUSION: The incidence of Type 1 diabetes in Kuwait is high compared with the neighbouring Arab countries, and it appears to be increasing as in many European populations.

Adolescent↗
PubMed2001

Causes of tonsillar disease and frequency of tonsillectomy operations.

OBJECTIVE: To characterize the factors that influence the frequency of tonsillectomy and adenoidectomy operations. DESIGN AND SETTING: Nationwide questionnaire. Analysis of patients undergoing tonsillectomy or adenoidectomy at Helsinki University Central Hospital, Helsinki, Finland. PARTICIPANTS: Four hundred eighty-three of 819 individuals randomly selected from the Finnish National Public Registry. Two thousand two hundred thirty-one individuals younger than 30 years who underwent tonsillectomy (888 patients), adenotonsillectomy (294 patients), or adenoidectomy (1049 patients) at Helsinki University Central Hospital from January 1, 1997, through December 31, 1998. MAIN OUTCOME MEASURES: Age of the individual at the time of operation. Indication for the operation. RESULTS: The frequency of adenoidectomies was 24% (116 persons) and that of tonsillectomies 8% (39 persons) among the 483 individuals who returned the questionnaire. The frequency of tonsillectomy operations by age was multimodal; the frequency of tonsillectomies increased in preschool-aged children, declined thereafter, and increased again in teenagers. Tonsillar hyperplasia was the most frequent among children younger than 10 years, peritonsillar abscesses among teenagers, and chronic tonsillitis among individuals older than 20 years. The proportion of females was higher than males among teenaged patients. However, the cause and sex distribution could not explain the multimodality in the age-specific frequency. The age-specific frequency of tonsillectomies performed because of peritonsillar abscesses still followed a multimodal distribution. CONCLUSIONS: Factors relating to respiratory tract infections, maturation of the immune system, and the onset of puberty contribute to the cause of tonsillar disease. Distinct indications for tonsillectomy should be defined for preschool-aged children, teenagers, and individuals older than 20 years.

Adenoidectomy↗
PubMed2001

Increasing incidence of childhood-onset type I diabetes in 3 Baltic countries and Finland 1983-1998.

AIMS/HYPOTHESIS: We aimed to study the incidence of Type I diabetes in 4 countries, Estonia, Latvia, Lithuania and Finland, during 1983-1998, focusing on the two separate periods of 1983-1990 and 1991-1998. METHODS: Population-based incidence data from nationwide diabetes registries were used. Crude and age-standardized incidence rates using the proportions of 39%, 32% and 29% for 5-year age groups (0-4, 5-9 and 10-14 years) were calculated. Yearly incidence was evaluated and the means between the two periods compared. RESULTS: Between 1983-1990 and 1991-1998 there was a statistically significant incidence increase in all 4 countries of Estonia, Lativia, Lithuania and Finland (relative risk 1.15, 95%-Confidence interval 1.10-1.19) and as well as in the 3 Baltic states of Estonia, Latvia, Lithuania (relative risk 1.13, 95%. Confidence interval 1.04-1.22). The crude incidence increased in Estonia from 10.1 (95%-Confidence interval 8.9-11.4) to 12.3 (11.0-13.8), in Latvia from 6.6 (5.8-7.3) to 7.4 (6.6-8.2) and in Lithuania from 6.8 (6.2-7.5) to 7.8 (7.1-8.5). In Finland the incidence rose from 34.6 (33.3-36.0) in 1983-1990 to 40.8 (39.4-42.2) in 1991-1998. In children under 5 years of a age a statistically important increase was seen in Estonia and Finland. The highest incidence for a single year was recorded for all participating countries in the late 1990 s. The highest annual incidence rate of childhood onset Type I diabetes in the world ever known was recorded in Finland in 1998 with 48.5 cases per 100 000 person-years. CONCLUSION/HYPOTHESIS: The incidence of Type I diabetes has increased since 1983 in the three Baltic states as well as in Finland. Long-term monitoring is needed for a better detection in changes in incidence.

Adolescent↗
PubMed2001

Bayesian analysis of geographical variation in the incidence of Type I diabetes in Finland.

AIMS/HYPOTHESIS: In Finland, the incidence of Type I (insulin-dependent) diabetes mellitus among children aged 14 years or under is the highest in the world. The increase in incidence is approximately 3% per year. A marked geographical variation in incidence was reported in Finland during the late 1980s. Our aim was to explore the most recent regional pattern in incidence of Type I diabetes in Finland. METHODS: Data on the nationwide incidence of childhood diabetes in Finland was obtained from the Prospective Childhood Diabetes Registry for the periods 1987-1991 and 1992-1996. Population data was obtained from the National Population Registry. The geographical pattern of incidence was studied applying a Bayesian hierarchical approach and Geographical Information Systems. The inferences from the data was based on the estimated geographical intensity of diabetes. RESULTS: There was a clear evidence of geographic variation for the risk of childhood diabetes during the entire 10-year period. The high-risk areas were found in the wide belt crossing the central part of Finland. Comparison of the estimated intensity of diabetes between the two 5-year periods showed that the geographical pattern of diabetes risk has changed over time. Our analyses also confirmed the existence of a few persistent high-risk and low-risk areas in Finland. CONCLUSION/INTERPRETATION: The finding of high-risk areas of childhood Type I diabetes suggests that specific genetic or environmental risk factors have become greater in certain geographic locations in Finland.

Adolescent↗
PubMed2000

Incidence of childhood type 1 diabetes worldwide. Diabetes Mondiale (DiaMond) Project Group.

OBJECTIVE: To investigate and monitor the patterns in incidence of childhood type 1 diabetes worldwide. RESEARCH DESIGN AND METHODS: The incidence of type 1 diabetes (per 100,000 per year) from 1990 to 1994 was determined in children < or =14 years of age from 100 centers in 50 countries. A total of 19,164 cases were diagnosed in study populations totaling 75.1 million children. The annual incidence rates were calculated per 100,000 population. RESULTS: The overall age-adjusted incidence of type 1 diabetes varied from 0.1/100,000 per year in China and Venezuela to 36.8/100,000 per year in Sardinia and 36.5/100,000 per year in Finland. This represents a >350-fold variation in the incidence among the 100 populations worldwide. The global pattern of variation in incidence was evaluated by arbitrarily grouping the populations with a very low (<1/100,000 per year), a low (1-4.99/100,000 per year), an intermediate (5-9.99/100,000 per year), a high (10-19.99/100,000 per year), and a very high (> or =20/100,000 per year) incidence. Of the European populations, 18 of 39 had an intermediate incidence, and the remainder had a high or very high incidence. A very high incidence (> or =20/ 100,000 per year) was found in Sardinia, Finland, Sweden, Norway Portugal, the U.K., Canada, and New Zealand. The lowest incidence (<1/100,000 per year) was found in the populations from China and South America. In most populations, the incidence increased with age and was the highest among children 10-14 years of age. CONCLUSIONS: The range of global variation in the incidence of childhood type 1 diabetes is even larger than previously described. The earlier reported polar-equatorial gradient in the incidence does not seem to be as strong as previously assumed, but the variation seems to follow ethnic and racial distribution in the world population.

Adolescent↗
PubMed2000

Mortality in patients with childhood-onset type 1 diabetes in Finland, Estonia, and Lithuania: follow-up of nationwide cohorts.

OBJECTIVE: To assess mortality of population-based cohorts of childhood-onset type 1 diabetic patients from the Eastern European countries of Estonia and Lithuania and compare this information with recent data from Finland. RESEARCH DESIGN AND METHODS: Estonian (n = 518) and Finnish (n = 5,156) type 1 diabetic cohorts were diagnosed between 1980 and 1994, and the Lithuanian (n = 698) cohort was diagnosed between 1983 and 1994. The mortality of these cohorts was determined in 1995. Life-table analysis, Cox survival analysis with covariates, and standardized mortality ratios (SMRs) were used. Causes of death were analyzed. RESULTS: Survival after 10 years duration of type 1 diabetes was similar in Estonia (94.3%) and Lithuania (94.0%), but much higher in Finland (99.1%). In the Cox survival analysis with covariates, the country of origin and age at diagnosis were found to be significant predictors of mortality. The SMR for the Estonian cohort was 4.35 (95% CI 2.25-7.61), the highest for the Lithuanian cohort was 7.55 (4.89-11.15), and the lowest for the Finnish cohort was 1.62 (1.10-2.28). The most common cause of death in Estonia and Lithuania was diabetic ketoacidosis (DKA), and in Finland, it was violent causes. No deaths from late complications of diabetes have been documented so far in any of the three countries. CONCLUSIONS: Our results demonstrate a high rate of short-term deaths due to DKA and inferior survival of childhood-onset type 1 diabetic patients in Estonia and Lithuania compared with Finland. In Finland, the survival of childhood-onset type 1 diabetic patients has improved and is only slightly inferior to that of the background population.

Adolescent↗
PubMed1999

Association between type 1 diabetes and Haemophilus influenzae type b vaccination: birth cohort study.

OBJECTIVES: To determine the effect of Haemophilus influenzae type b vaccination and its timing on the risk of type 1 diabetes in Finnish children. DESIGN: Cumulative incidence and relative risk of type 1 diabetes was compared among three birth cohorts of Finnish children: those born during the 24 months before the H influenzae type b vaccination trial, those in the trial cohort who were vaccinated at 3 months of age and later with a booster vaccine, and those in the trial cohort who were vaccinated at 24 months of age only. The probability of type 1 diabetes was estimated using regression analysis assuming that there were no losses to 10 year follow up and no competing risks. SETTING: Finland (total population 5 million and annual birth rate 1.3%). SUBJECTS: 128 936 children born from 1 October 1983 to 1 September 1985, and 116 352 children born from 1 October 1985 to 31 August 1987. MAIN OUTCOME MEASURES: Probability of type 1 diabetes among children vaccinated with H influenzae type b and non-vaccinated children. RESULTS: No statistically significant difference was found at any time during the 10 year follow up in the risk of type 1 diabetes between the children born before the vaccination period and those vaccinated at the age of 24 months only (relative risk 1.01). The difference in the risk between the cohort vaccinated first at the age of 3 months and the cohort vaccinated at the age of 24 months only was not statistically significant either (1.06). CONCLUSION: It is unlikely that H influenzae type b vaccination or its timing cause type 1 diabetes in children.

Age Factors↗
PubMed1999

Record-high incidence of Type I (insulin-dependent) diabetes mellitus in Finnish children. The Finnish Childhood Type I Diabetes Registry Group.

AIMS/HYPOTHESIS: In Finland, the incidence of Type I (insulin-dependent) diabetes mellitus in children aged 14 years or under is the highest in the world and the trend in incidence has been increasing. Our aim was to determine the most recent trends in incidence and the age distribution at diagnosis of Type I diabetes. METHODS: Data on the incidence of Type I diabetes in Finland nationwide were obtained from two sources: for the period 1965 to 1986 from the Central Drug Registry of the Social Insurance Institution and for the period 1987 to 1996 from the prospective childhood Type I diabetes registry. The annual incidence was calculated per 100,000 people. The increase and the trend in incidence were estimated by fitting the linear regression model with the annual incidence data. RESULTS: During 1987 to 1993 the incidence of Type I diabetes seemed to be rather stable at 36 per 100,000 per year. The incidence has continued to increase thereafter and reached 45 per 100,000 per year in 1996. The analysis of the long-term trend in incidence between 1965 and 1996 showed an absolute incidence increase of 0.67 per year on average being 3.4 % compared with the incidence in 1965. The increase from 1987 to 1996 was highest in very young children 1-4 years old at diagnosis. CONCLUSION/INTERPRETATION: The high incidence of Type I diabetes in Finnish children has thus far not levelled off but is increasing further. If the trend continues, the predicted incidence in Finland will be approximately 50 per 100,000 per year in the year 2010.

Adolescent↗
PubMed1999

Worldwide increase in incidence of Type I diabetes--the analysis of the data on published incidence trends.

AIMS/HYPOTHESIS: Several reports on the incidence of Type I (insulin-dependent) diabetes mellitus have suggested that the incidence is increasing. The aim of this study was to find out whether the incidence is increasing globally or restricted to a selected populations only and to estimate the magnitude of the change in incidence. METHODS: During 1960 to 1996 37 studies in 27 countries were carried out. To fulfil the inclusion criteria the study periods ranged from 8-32 years. The temporal trend was fitted by linear regression, with the logarithm of the age-standardized incidence as the dependent variable and the calendar year as the independent variable. Then, the regression coefficient (x 100%) is approximately the average relative increase in incidence per year (as percentage). RESULTS: Results from the pooled data from all 37 populations showed that the overall increase in incidence was 3.0% per year (95% CI 2.6; 3.3, p = 0.0001). The statistically significant increase was found in 24 of 37 populations including all high incidence (> 14.6 per 100000 a year) populations. The relative increase was, however, steeper in the populations with a lower incidence. The correlation between logarithm of the incidence and the increase in incidence was r = -0.56, p = 0.0004. CONCLUSION/INTERPRETATION: The incidence of Type I diabetes is increasing worldwide both in low and high incidence populations. By the year 2010 the incidence will be 50 per 100000 a year in Finland and also in many other populations it will exceed 30 per 100000 a year.

Adolescent↗
PubMed1999

Seasonal variation in the incidence of Type 1 diabetes mellitus during 1983 to 1992 in the countries around the Baltic Sea.

AIM: To examine seasonal patterns of incidence of Type 1 diabetes mellitus incidence in children aged 0-14 years in Finland, Sweden, Estonia, Latvia and Lithuania during 1983-1992 (1987-1992 for Finland). METHODS: The study used a method that models incidence data using combinations of sine waves to model seasonal variation around a possible linear trend. RESULTS: In Finland, a significant pattern was found for combined sexes and age groups 0-9 and 10-14 years. A significant pattern was also confirmed for 10-14 year-old boys. In Sweden, the best model with significant pattern was found separately for boys and girls and age groups 0-9 and 10-14 years, however, a significant pattern was confirmed for older girls only. A seasonal pattern in older boys in Finland and girls in Sweden was characterized by two cycles with decreased incidence in June and November-December. The pattern among younger children (0-9 or 5-9 years) had one cycle with a decreased incidence in May-June. In Estonia, a significant pattern was found for the age group 0-14 years and combined sexes. No significant seasonal patterns were found in Latvia and Lithuania. CONCLUSIONS: The seasonal pattern with two cycles among older children and one cycle only among younger children may indicate different triggers of Type 1 diabetes mellitus for different age groups.

Adolescent↗
PubMed1999

The onset age of type 1 diabetes in Finnish children has become younger. The Finnish Childhood Diabetes Registry Group.

OBJECTIVE: To analyze the change in the age distribution at onset of type 1 diabetes in boys and girls aged 1-14 years during a 32-year period (from 1965 to 1996). RESEARCH DESIGN AND METHODS: Data on the incidence of type 1 diabetes in Finland were obtained from the Central Drug Registry of the Social Insurance Institution for 1965-1986 (6,195 cases) and from the Prospective Childhood Diabetes Registry for 1987-1996 (3,613 cases). The change in age- and sex-specific incidence was estimated by fitting the linear regression with the logarithm of the annual incidence data. Analysis of variance was used to compare the trends between the various age-groups (1-4, 5-9, and 10-14 years) and sexes. RESULTS: The incidence of type 1 diabetes increased predominantly in the younger age-groups. In children aged 1-4 years, the increase was 4.2% per year, and the overall 32-year relative increase was 338%. For children aged 5-9 and 10-14 years, the increase was 2.5 and 1.3% per year, respectively, and the overall relative increase was 116 and 49%, respectively. In boys aged 1-9 years, the increase was greatest from 1965 to 1984, whereas in girls aged 1-9 years, the statistically significant increase occurred between 1985 and 1996. In children aged 10-14 years, the only significant increase was seen in boys from 1965 to 1974 (3.7% per year). CONCLUSIONS: The greatest increase in the incidence of type 1 diabetes mainly occurred in children aged < 5 years. The incidence in young boys has been increasing since the mid-1960s, whereas in young girls, the significant increase began later, around the mid-1970s. In children aged 10-14 years, the increase in incidence has leveled off.

Adolescent↗