Effects of a home-based, exergaming intervention on physical function and pain after total knee replacement in older adults: a randomised controlled trial

Objectives

To investigate the effects of 4 months of customised, home-based exergaming on physical function and pain after total knee replacement (TKR) compared with standard exercise protocol.

Methods

In this non-blinded randomised controlled trial, 52 individuals aged 60-75 years undergoing TKR were randomised into an exergaming (intervention group, IG) or a standard exercising group (control group, CG). Primary outcomes were physical function and pain measured before and after (2 months and 4 months) surgery using the Oxford Knee Score (OKS) and Timed Up and Go (TUG) test. Secondary outcomes included measures of the Visual Analogue Scale, 10m walking, short physical performance battery, isometric knee extension and flexion force, knee range of movement and satisfaction with the operated knee.

Results

Improvement in mobility measured by TUG was greater in the IG (n=21) at 2 (p=0.019) and 4 months (p=0.040) than in the CG (n=25). The TUG improved in the IG by -1.9 s (95% CI, -2.9 to -1.0), while it changed by -0.6 s (95% CI -1.4 to 0.3) in the CG. There were no differences between the groups in the OKS or secondary outcomes over 4 months. 100% of patients in the IG and 74% in the CG were satisfied with the operated knee.

Conclusion

In patients who have undergone TKR, training at home with customised exergames was more effective in mobility and early satisfaction and as effective as standard exercise in pain and other physical functions. In both groups, knee-related function and pain improvement can be considered clinically meaningful.

Trial registration number

NCT03717727.

Effectiveness of Gamification in Knee Replacement Rehabilitation: Protocol for a Randomized Controlled Trial With a Qualitative Approach

BACKGROUND

Exergames can provide encouraging exercise options. Currently, there is limited evidence regarding home-based exergaming in the postoperative phase of total knee replacement (TKR).

OBJECTIVE

This study aimed to investigate the effects of a 4-month postoperative home-based exergame intervention with an 8-month follow-up on physical function and symptoms among older persons undergoing TKR compared with home exercise using a standard protocol. In addition, a concurrent embedded design of a mixed methods study was used by including a qualitative component within a quantitative study of exergame effects.

METHODS

This was a dual-center, nonblinded, two-arm, parallel group randomized controlled trial with an embedded qualitative approach. This study aimed to recruit 100 patients who underwent their first unilateral TKR (aged 60-75 years). Participants were randomized to the exergame or standard home exercise arms. Participants followed a custom-made exergame program independently at their homes daily for 4 months. The primary outcomes at 4 months were function and pain related to the knee using the Oxford Knee Score questionnaire and mobility using the Timed Up and Go test. Other outcomes, in addition to physical function, symptoms, and disability, were game user experience, exercise adherence, physical activity, and satisfaction with the operated knee. Assessments were performed at the preoperative baseline and at 2, 4, and 12 months postoperatively. Exergame adherence was followed from game computers and using a structured diary. Self-reported standard exercise was followed for 4 months of intervention and physical activity was followed for 12 months using a structured diary. Qualitative data on patients' perspectives on rehabilitation and exergames were collected through laddering interviews at 4 and 12 months.

RESULTS

This study was funded in 2018. Data collection began in 2019 and was completed in January 2022. The COVID-19 pandemic caused an unavoidable situation in the study for recruitment, data collection, and statistical analysis. As of November 2020, a total of 52 participants had been enrolled in the study. Primary results are expected to be published by the end of 2022.

CONCLUSIONS

Our study provides new knowledge on the effects of postoperative exergame intervention among older patients with TKR. In addition, this study provides a new understanding of gamified postoperative rehabilitation, home exercise adherence, physical function, and physical activity among older adults undergoing TKR.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03717727; https://clinicaltrials.gov/ct2/show/NCT03717727.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/38434.

The nature of co-morbid psychopathology in adolescents with gender dysphoria

Gender-referred adolescents (GR) have been reported to present with considerable psychiatric symptomatology compared to their age-peers. There is, however, little research on how they compare to adolescents referred due to mental health problems (MHR). We set out to compare psychopathology in adolescents referred to our specialized gender identity unit (n = 84) and adolescents referred to a general adolescent psychiatric clinic (n = 293) in a university hospital setting in Finland. Of the GR adolescents, 40.9% had not received any psychiatric diagnosis during adolescence. Eating disorders were less common in the GR than in the MHR group, but otherwise the prevalences of disorders did not differ statistically significantly. At the symptom level, the GR adolescents displayed significantly more suicidal ideation and talk and less alcohol abuse and eating disorder symptoms than did the MHR adolescents, but otherwise their symptom profiles were comparable. Additionally, the GR adolescents had significantly fewer total externalizing symptoms than did the MHR adolescents. Adolescents seeking gender affirming treatments present with psychiatric symptoms and disorders comparable to those seen among adolescent psychiatric patients. Medical gender affirming care may not be a sufficient intervention for treating psychiatric comorbidities of adolescents with gender dysphoria.

Implant Survival of Constrained Acetabular Device in Primary Total Hip Arthroplasty Based on Data From the Finnish Arthroplasty Register

BACKGROUND

Constrained acetabular devices were developed to prevent dislocations after total hip arthroplasty (THA). However, the data on their success have been contradictory. In this study, we aimed to assess implant survival of the constrained acetabular device in primary THA based on the Finnish Arthroplasty Register data.

METHODS

A total of 373 primary THAs with constrained acetabular devices inserted from 2006 to 2017 were included. A reference group was formed on a 1:3 basis and matched for age, sex, and diagnosis, consisting of 1118 conventional THAs. Implant survival estimates using death as a competing risk were assessed with revision for any reason and for any aseptic reason as the endpoints. The Cox multiple regression models were adjusted for age, sex, and diagnosis. The mean follow-up time was 3.3 (0-12.4) years for the constrained device group and 3.8 (0-12.0) years for the reference group.

RESULTS

Overall, there were 21 revisions in the constrained device group and 49 in the reference group. The 8-year survivorship for any reason was 94% (confidence interval [CI]: 91-96) for the constrained device group and 93% (CI: 89-97) for the reference group. With revision for any aseptic reason as the endpoint, the 8-year survivorships were 97% (CI: 95-99) and 94% (CI: 90-98), respectively. During the first 1.5 years, the constrained acetabular device group had a similar revision risk (hazard ratio: 1.09 [CI: 0.57-2.07], P = .8) to that of the reference group.

CONCLUSION

The constrained acetabular device had good survival in primary THA, and our results support its continued use even in high-risk patients.

Survival of 11,390 Continuum cups in primary total hip arthroplasty based on data from the Finnish Arthroplasty Register

Background and purpose - The use of trabecular metal (TM) cups for primary total hip arthroplasty (THA) is increasing. Some recent data suggest that the use of TM in primary THA might be associated with an increased risk of revision. We compared implant survival of Continuum acetabular cups with other commonly used uncemented cups. Patients and methods - Data on 11,390 primary THAs with the Continuum cup and 30,372 THAs with other uncemented cups (reference group) were collected from the Finnish Arthroplasty Register. Kaplan-Meier survival estimates were calculated; the endpoint was revision for any reason, for infection, or for dislocation. Revision risks were assessed with adjusted Cox multiple regression models. A subgroup analysis on the use of neutral or elevated liners in the Continuum group was made. Results - The 7-year survivorship of the Continuum group was 94.6% (95% CI 94.0-95.2) versus 95.6% (CI 95.3-95.8) in the reference group for revision for any reason. The risk for revision was higher in the Continuum group than in the reference group both for revision for any reason (HR 1.3 [CI 1.2-1.5)]) and for revision for dislocation (HR 1.9 [CI 1.5-2.3]). There was no difference in the rates of revision because of infection (HR 0.99 [CI 0.78-1.3]). Use of a neutral liner increased the risk for revision due to dislocation in comparison with the use of an elevated rim liner in the Continuum group (HR 1.7 [CI 1.2-2.5]). Interpretation - THA with Continuum cups is associated with an increased risk of revision compared with other uncemented cups, mainly due to revisions because of dislocation. Our results support the use of an elevated liner when Continuum cups are used for primary THA.

Poor 10-year survivorship of hip resurfacing arthroplasty

Background and purpose - In a previous registry report, short-term implant survival of hip resurfacing arthroplasty (HRA) in Finland was found to be comparable to that of total hip arthroplasty (THA). Since then, it has become evident that adverse reactions to metal debris (ARMDs) may also be associated with HRA, not only with large-diameter head metal-on-metal THA. The aim of the study was to assess medium- to long-term survivorship of HRA based on the Finnish Arthroplasty Register (FAR). Patients and methods - 5,068 HRAs performed during the period 2001-2013 in Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities and their 95% confidence intervals (CIs). Cox multiple regression, with adjustment for age, sex, diagnosis, femoral head size, and hospital volume was used to analyze implant survival of HRA devices with revision for any reason as endpoint. The reference group consisted of 6,485 uncemented Vision/Bimetric and ABG II THAs performed in Finland over the same time period. Results - The 8-year survival, with any revision as an endpoint, was 93% (CI: 92-94) for Birmingham Hip Resurfacing (BHR), 86% (CI: 78-94) for Corin, 91% (CI: 89-94) for ReCap, 92% (CI: 89-96) for Durom, and was 72% (CI: 69-76) for the Articular Surface Replacement (ASR). The 10-year survival, with any revision as an endpoint, for reference THAs was 92% (CI: 91-92) and for all HRAs it was 86% (CI: 84-87%). Female HRA patients had about twice the revision risk of male patients. ASR had an inferior outcome: the revision risk was 4-fold higher than for BHR, the reference implant. Interpretation - The 10-year implant survival of HRAs is 86% in Finland. According to new recommendations from NICE (The National Institute for Health and Care Excellence), an HRA/THA should have a revision rate of 5% or less at 10 years. None of the HRAs studied achieved this goal.

Freedom Constrained Liner for the Treatment and Prevention of Dislocation in Total Hip Arthroplasty

BACKGROUND AND PURPOSE

Dislocation is one of the most common complications following total hip arthroplasty. The aim of our study was to assess failure rate of the Biomet Freedom constrained liner (Biomet, Warsaw, IN, USA) either in revision surgery for recurrent dislocation, or as a preventive method in high dislocation risk patients.

PATIENTS AND METHODS

We assessed retrospectively 105 consecutive surgical procedures in 103 patients where a Freedom constrained liner or cup was used in Turku University Hospital over a 7-year period from 2007 to 2014. The mechanical failure rate of the device was assessed based on medical records. The average age of the patients was 73.4 years. The number of male patients was 53 (51%). Mean follow-up time was 2.5 years. The association between failure of the device and potential risk factors-age, gender, indication, and approach-was analyzed with logistic regression. Results were expressed by odd ratios and 95% confidence intervals.

RESULTS

The mechanical failure rate of the Freedom device was 6 out of 105 (5.7%). None of the 11 preventive primary THAs against dislocation failed, 4 out of 52 (7.7%) preventive revision THAs against dislocation failed, and 2 out of 42 (4.8%) of the treated dislocation cases failed. Four out of six failures were dislocations due to impingement and failure of the locking mechanism. Two liners failed because of loosening. The risk factors assessed were not associated with failure of the device.

INTERPRETATION

We found out that the mechanical failure rate of a Freedom constrained device was low. These results encourage us to continue using the device.

Seasonal variation of diagnosis of Type 1 diabetes mellitus in children worldwide

AIMS

To determine if there is a worldwide seasonal pattern in the clinical onset of Type 1 diabetes.

METHODS

Analysis of the seasonality in diagnosis of Type 1 diabetes was based on the incidence data in 0- to 14-year-old children collected by the World Health Organization Diabetes Mondiale (WHO DiaMond) Project over the period 1990-1999. One hundred and five centres from 53 countries worldwide provided enough data for the seasonality analysis. The incidence seasonality patterns were also determined for age- and sex-specific groups.

RESULTS

Forty-two out of 105 centres exhibited significant seasonality in the incidence of Type 1 diabetes (P < 0.05). The existence of significant seasonal patterns correlated with higher level of incidence and of the average yearly counts. The correlation disappeared after adjustment for latitude. Twenty-eight of those centres had peaks in October to January and 33 had troughs in June to August. Two out of the four centres with significant seasonality in the southern hemisphere demonstrated a different pattern with a peak in July to September and a trough in January to March.

CONCLUSIONS

The seasonality of the incidence of Type 1 diabetes mellitus in children under 15 years of age is a real phenomenon, as was reported previously and as is now demonstrated by this large standardized study. The seasonality pattern appears to be dependent on the geographical position, at least as far as the northern/southern hemisphere dichotomy is concerned. However, more data are needed on the populations living below the 30th parallel north in order to complete the picture.

Childhood BMI trajectories and the risk of developing young adult-onset diabetes

AIMS/HYPOTHESIS

The aim of this study was to examine the effects of childhood BMI growth dynamics on the risk of developing young adult-onset type 1 and type 2 diabetes.

METHODS

Finnish national healthcare registers were used to identify individuals with diabetes diagnosed between 1992 and 1996 at 15-39 years of age. Non-diabetic control participants were chosen from the National Population Registry. Anthropometric measurements were obtained from the original child welfare clinic records. Only the case-control pairs with sufficient growth data recorded were included in the analyses (218/1,388 for type 1 diabetes [16%] and 64/1,121 for type 2 diabetes [6%]). Two developmental stages in BMI growth (the points of infancy maximum BMI and the BMI rebound) were examined, and conditional logistic regression was applied to the variables of interest.

RESULTS

The risk for type 1 diabetes increased 1.19-fold per 1 kg/m(2) rise in the infancy maximum BMI (p = 0.02). In addition, there was a 1.77-fold increase in the risk for type 2 diabetes per 1 kg/m(2) rise in the level of BMI at the BMI rebound (p = 0.04). Higher values of BMI at these points corresponded to a larger BMI gain from birth to that developmental stage. Age at the infancy maximum BMI or age at the BMI rebound did not affect the risk for either type of diabetes.

CONCLUSIONS/INTERPRETATION

The BMI gain in infancy among individuals who subsequently developed young adult-onset type 1 diabetes was faster than that of those who remained healthy. The excess BMI gain in individuals who developed young adult-onset type 2 diabetes could already be seen during early childhood.

The effect of birth order and parental age on the risk of type 1 and 2 diabetes among young adults

AIMS/HYPOTHESIS

The aim of this study was to examine the effects of birth order and parental age on the risk of type 1 and type 2 diabetes among Finnish individuals aged 15-39 years.

METHODS

Data on all cases of type 1 diabetes (n = 1,345) and type 2 diabetes (n = 1,072), diagnosed between 1992 and 1996, were collected from four sources: standardised national reports from diabetes nurses, the National Hospital Discharge Register, the Drug Prescription Register and the Drug Reimbursement Register. Information on matched controls and the family members of all study subjects were obtained from the National Population Registry. The odds ratios (ORs) for both types of diabetes were estimated using a conditional logistic regression model.

RESULTS

There was a U-shaped relationship between maternal age and the risk of type 2 diabetes in the offspring: the risk was higher in children born to young and old mothers compared with children born to mothers aged around 30 years. The children born second (OR 0.76, 95% CI 0.62-0.94), third (OR 0.73, 95% CI 0.55-0.95), or fourth (OR 0.66, 95% CI 0.47-0.94) had a lower risk of type 2 diabetes than the first-born children. Maternal age, paternal age, and birth order did not have an effect on the risk of type 1 diabetes in the individuals aged 15-39 years at the time of diagnosis.

CONCLUSIONS/INTERPRETATION

Maternal age and birth order are both associated with the risk of early-onset type 2 diabetes. However, part of these associations may be due to low birthweight. In this study neither parental age nor birth order showed a significant association with the risk of type 1 diabetes diagnosed after 15 years of age.

A high incidence of type 1 diabetes and an alarming increase in the incidence of type 2 diabetes among young adults in Finland between 1992 and 1996

AIMS/HYPOTHESIS

The aim of this study was to examine the incidence and trends of type 1 and type 2 diabetes in the 15-39 year-old population between 1992 and 1996 in Finland.

SUBJECTS AND METHODS

Data on the nationwide incidence of diabetes were obtained from four data sources: standardised reports from diabetes nurses, the Finnish National Hospital Discharge Register, the Drug Reimbursement Register and the Drug Prescription Register. The inclusion criterion was consistency in the diagnosis of diabetes across at least two data sources. The sex- and age-specific incidence was calculated for 5-year age groups, both for type 1 and type 2 diabetes. The effects of age, sex and year of diagnosis were assessed by fitting the linear regression model to the incidence data.

RESULTS

Between 1992 and 1996 the age-adjusted incidence of type 1 diabetes among 15-39 year olds was 15.9 per 100,000/year. The incidence was highest among the 15-19 year olds and decreased with age. Conversely, the incidence of type 2 diabetes was very low among 15-19 year olds and increased with age. The total age-adjusted incidence of type 2 diabetes among 15-39 year olds was 11.8 per 100,000/year. The average annual increase in the incidence of type 2 diabetes was 7.9% (95% CI 3.7-12.2%).

CONCLUSIONS/INTERPRETATION

The age at which the Finnish population is at risk of type 1 diabetes extends into young adulthood. The rapid increase in the incidence of type 2 diabetes in the young adult population is a current public health problem.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.