A low incidence of Type 1 diabetes between 1977 and 2001 in south-eastern Sweden in areas with high population density and which are more deprived.

AIMS: To explore how socioeconomic factors and population density may contribute to the geographical variation of incidence of Type 1 diabetes in children in south-eastern Sweden. METHOD: All children diagnosed with Type 1 diabetes in south-eastern Sweden during 1977-2001 were defined geographically to their place of residence and were allocated x and y coordinates in the national grid. The population at risk and socioeconomic data were aggregated in 82,000 200-m squares and geocoded likewise. A socioeconomic index was calculated using a signed chi(2) method. Rural-urban gradients were defined by overlay analysis in a geographic information system. RESULTS: The incidence during the past 25 years has been rising steadily, particularly in the last 6 years. The incidence was highest in areas with a high proportion of small families, of families with a high family income and better education, and this was found both at the time of diagnosis and at the time of birth. In the rural-urban analysis, the lowest incidence was found in the urban area with > 20,000 inhabitants, where there was also a higher frequency of deprivation. CONCLUSIONS: Our findings indicate that geographical variations in incidence rates of Type 1 diabetes in children are associated with socioeconomic factors and population density, although other contributing factors remain to be explained.

Seasonal variation in the diagnosis of type 1 diabetes in south-east Sweden.

With the aim to survey the seasonal pattern of diagnosis of type 1 diabetes we included all 1903 children <16 years of age and who had been diagnosed with type 1 diabetes between 1977 and 2001 in the south-east of Sweden. To investigate the seasonal pattern a mixture of two cosine functions was included in a logistic regression model. There was a clear seasonal variation over the years (p<0.001). Children in the oldest age group (11-15 years) showed the most obvious seasonal variation (p<0.001). Children with a short duration of symptoms had about the same seasonal variation as children with a long duration. Both children with and without an infection 3 months prior to diagnosis showed significant seasonal variation (p<0.001) although the seasonal pattern differed between the two groups (p<0.001). As the incidence of diabetes increased during the 25 years the study period was divided into periods of 5 years and it was only during the two last periods that significant seasonal variation occurred. There is a clear seasonal variation in diagnosis of type 1 diagnosis in children and the results suggest that children with a less aggressive disease process at diagnosis were most responsible for this variation. Children with and without prior infection showed a different seasonal pattern.

Geographical mapping of type 1 diabetes in children and adolescents in south east Sweden.

STUDY OBJECTIVE: As earlier studies have shown space-time clusters at onset of type 1 diabetes in the south east region of Sweden we investigated if there also has been any geographical clusters of diabetes in this region. DESIGN: The place of residence (coordinates) at the time of diagnosis were geocoded in a geographical information system (GIS). All children diagnosed with type 1 diabetes up to 16 years of age at diagnosis between 1977-1995 were included. The population at risk was obtained directly from the population registry for the respective years and geographical area levels. SETTING: South east region of Sweden containing 5 counties, 49 municipalities, and 525 parishes. MAIN RESULTS: A significant geographical variation in incidence rate were found between the municipalities (p<0.001) but not between the counties. The variation became somewhat weaker when excluding the six largest municipalities (p<0.02). In municipalities with increased risk (>35.1/100 000) the major contribution comes from children in age group 6-10 years of age at diagnosis. There were no obvious differences between the age groups in municipalities with decreased risk (<20.1/100 000). Boys and girls had about the same degree of geographical variation. CONCLUSIONS: Apart from chance, the most probable explanation for the geographical variation in the risk for children and adolescents to develop type 1 diabetes between the municipalities in the region is that local environmental factors play a part in the process leading to the disease.

Health-related quality of life after osteoporotic fractures.

OBJECTIVE: To estimate the impact of osteoporosis fractures on health-related quality of life (HRQOL) in postmenopausal women. METHODS: To compare the impact on HRQOL of different osteoporotic fractures, 600 consecutive women 55-75 years old with a new fracture (inclusion fracture) were invited by mail. After exclusions by preset criteria (high-energy fractures, ongoing osteoporosis treatment, or unwillingness to participate), 303 women were included, 171 (56%) of whom had a forearm, 37 (12%) proximal humerus, 40 (13%) hip, and 55 (18%) vertebral fracture, respectively, and all were investigated and treated according to the current local consensus program for osteoporosis. In addition, HRQOL was evaluated by the SF-36 questionnaire and compared with local, age-matched reference material. Examinations were performed 82 days (median) after the fracture and 2 years later. RESULTS: HRQOL was significantly reduced at baseline regarding all SF-36 domains after vertebral fractures and most after hip fractures, but only regarding some domains after forearm and humerus fracture. After 2 years, improvements had occurred after all types of fractures, and after forearm or humerus fracture, HRQOL was completely normalized in all domains. However, 2 years after hip fracture, HRQOL was still below normal regarding physical function, role-physical and social function, while after vertebral fracture, scores were still significantly lower for all domains, physical as well as mental. Patients with one or more previous fractures before the inclusion fracture had lower HRQOL at baseline and after 2 years, compared with those with no previous fracture. Patients with osteoporosis (T-score <-2.5 in hip or spine) had lower HRQOL than those with normal BMD. CONCLUSION: Vertebral and hip fractures have a considerably greater and more prolonged impact on HRQOL than forearm and humerus fractures. The number of fractures was inversely correlated to HRQOL. These differences should be taken into account when making priorities in health care programs.

Changes in hip fracture epidemiology: redistribution between ages, genders and fracture types.

After several reports of increasing hip fracture incidence some studies have suggested a trend-break. In a previous study of hip fractures we forecast a 70% increase in the total number of fractures from 1985 up to year 2000. We therefore studied the incidence trend for the last 15 years and supply a new prognosis up to year 2010. We recorded all incident hip fractures treated in the county of Ostergötland, Sweden (approximately 400,000 inhabitants) 1982-96. A total of 11,517 hip fractures in men and women aged 50 years and above were included in the study after cross-validation between a computerized register of radiologic investigations and the hospital records. The projected number of fractures up to year 2010 was estimated by a Poisson regression model, considering both age and year of fracture in every single year 1982-96 for the respective fracture type and gender, and applied to the projected population. The annual number of hip fractures increased by 39% in men and 25% in women during the study period. Amongst men, the age-adjusted incidence of cervical fractures increased from 188 to 220/100,000 and of trochanteric fractures from 138 to 170/100,000. In women the incidence of cervical fractures decreased from 462/100,000 to 418/100,000 and of trochanteric fractures from 407/100,000 to 361/100,000. Cervical/trochanteric fracture incidence rate ratio leveled off, and also the female/male fracture rate ratio declined. A prognosis assuming that the incidence development will continue as during 1982-96, and a population in agreement with the forecast, predicts that the total age- and sex-adjusted number of hip fractures will decrease by 11% up to year 2010 compared with 1996. In women and men, however, a decrease of 19% and an increase of 7% respectively were projected. If the age- and sex-specific incidence remains at the same level as at the end of the study period, no significant change in the total numbers will occur. A trend-break was thus found in hip fracture incidence for women but not for men. Whether this is due to therapeutic and/or preventive measures in women is unknown. According to the most probable scenario a substantial increase in male trochanteric fractures (36%) is expected up to 2010, while all other hip fractures in both genders will decrease by 4-32% resulting in a total reduction of 11%.

Aluminum concentration in deciduous teeth is dependent on tooth type and dental status.

Aluminum (Al) concentration was assessed in deciduous teeth in relation to sex, year of birth, tooth type, and the presence of caries and roots. Three hundred and twenty-three deciduous teeth from children born during the period 1952 93 in a county in southeast Sweden were sampled, and the Al content determined by graphite furnace atomic absorption spectrophotometry. The arithmetic mean of the Al concentration was 0.58 +/- 0.64 ppm dry weight (mean +/- standard deviation) and differed significantly between incisors (1.05 +/- 1.04 ppm) and canines (0.48 +/- 0.50 ppm) and between incisors and molars (0.53 +/- 0.55 ppm). A significant difference was found between teeth with and without caries. No significant differences were found between sexes. The Al concentration correlated significantly with tooth weight for incisors (r = -0.47) and canines (r = -0.45) but not for molars (r = 0.03). No significant change in Al concentration was found over time. Caries-free deciduous molars are suggested as the most useful teeth for biological monitoring of aluminum.

Childhood leukaemia in areas with different radon levels: a spatial and temporal analysis using GIS.

OBJECTIVES: To evaluate the relation between exposure to ground radon levels and leukaemia among children using existing population and disease registers. DESIGN: Ecological correlation study. SETTING: The county of Ostergötland in Sweden. METHODS: Every child born in the county between 1979 and 1992 was mapped to the property centroid coordinates by linking addresses in the population and property registers. Population maps were overlaid with radon maps and exposure at birth and each subsequent year was quantified as high, normal, low or unknown. This was analysed with data from the tumour registry. Standardised mortality ratios (SMRs) were calculated using the age and sex specific rates for Sweden for the year 1995. RESULTS: 90 malignancies occurred among 53 146 children (498 887 person years) who formed the study population. SMRs for acute lymphatic leukaemia (ALL) among children born in high, normal and low risk areas were 1.43, 1.17 and 0.25 respectively. The relative risk for the normal risk group and high risk group as compared with the low risk group was 4.64 (95% CI 1.29, 28.26) and 5. 67 (95% CI 1.06, 42.27). The association between ALL and continued residence at normal or high risk areas showed a similar trend. No association between radon risk levels and any other malignancy was seen. CONCLUSION: Children born in and staying at areas where the risk from ground radon has been classified as low are less likely to develop ALL than those born in areas classified as normal and high risk.

Bone mineral density in diagnosis of osteoporosis: reference population, definition of peak bone mass, and measured site determine prevalence.

A population-based study was performed in order to compare different definitions of peak bone mass, and to apply the corresponding T-scores for different skeletal sites to a cohort of 70-yr-old women for studying the prevalence of osteoporosis. Bone mineral density (BMD) of the hip, lumbar spine, and forearm was measured by dual X-ray absorptiometry (Hologic 4500) in 296 women ages 16-31 yr and 210 women age 70 yr. Peak bone mass occurred in women in their early 20s at the proximal femur and at 28 and 31 yr at the spine and forearm, respectively. BMD cutoff levels were compared to machine-specific cutoff values for the different sites. When applied to our cohort of 70-yr-old women, the prevalence of osteoporosis at the total hip was 9-25%, depending on which peak bone mass the T-score of -2.5 was based. The prevalence in the spine was 28-33% and in the forearm 45-67%. Osteoporosis in at least one of the three measured sites was documented in 49-72% of the population sample. Our results show that the use of T-score to define osteoporosis results in a highly different prevalence rate in a given population depending on the reference population and the skeletal sites chosen for measurement.

Three years' follow-up of bone density in adult coeliac disease: significance of secondary hyperparathyroidism.

BACKGROUND: The mechanisms of disturbances in bone mineral density (BMD) in coeliac disease are not completely understood. The aim of this prospective study was to investigate the possible significance of secondary hyperparathyroidism (SHPT) with regard to BMD in patients with untreated coeliac disease. METHODS: One hundred and five adult patients with untreated coeliac disease were examined for BMD and serum parathyroid hormone (PTH) concentration. BMD in the hip, lumbar spine, and forearm were examined up to 3 years after the introduction of a gluten-free diet. RESULTS: SHPT was found in 27% (28 of 105) of the patients. In patients with SHPT serum levels of 25-hydroxy-vitamin D were lower and those of alkaline phosphatase higher than in patients with normal PTH, but ionized serum calcium did not differ between the two groups. BMD was more severely reduced in patients with SHPT. Although the BMD increment was more rapid in patients with than in those without SPTH, only in the latter group did mean BMD became normal after 1-3 years on a gluten-free diet (GFD). After 3 years on a GFD more than half of the patients with initial SHPT still had low BMD in both the hip and the forearm. Furthermore, in patients with SHPT the intestinal mucosa more often remained atrophic at the 1-year follow-up, despite good compliance with the diet. CONCLUSIONS: Low BMD in patients with untreated coeliac disease is often associated with SHPT. After 3 years on a GFD the BMD remains low only in patients with initial SHPT. We therefore suggest that PTH should be measured when the diagnosis of coeliac disease is made, as an indicator of more serious intestinal disorder and complicating bone disease.

Allergic disease in teenagers in relation to urban or rural residence at various stages of childhood.

BACKGROUND: Higher prevalences of allergic diseases and IgE antibodies to inhalant allergens have been reported for persons living in urban areas than for persons living in rural areas. METHODS: Associations between cumulative incidences of allergic diseases in 1878 children aged 13-14 years and their place of residence (urban, semiurban, or rural) from birth were assessed by questionnaire (ISAAC), in order to find out whether there is a period of increased sensitivity to external influences during the first few years of life. Family history and exposure to pets, tobacco smoke, and damp were considered in multiple regression. RESULTS: There was a significantly higher prevalence of allergic diseases with urban residence than with rural residence during the first 2 years of life (e.g., for bronchial asthma, relative risk (RR) for the first year 2.1, 95% CI 1.2-3.7). An increased risk was still found after multiple regression (RR=1.7). Semiurban residence was associated with an intermediate cumulative incidence of allergic diseases. Maternal smoking during pregnancy was associated with asthma (RR=1.4, 95% CI 1.0-2.0). CONCLUSIONS: The findings support a period of increased susceptibility during the first years of life. Whether rural lifestyle protects against allergy or whether urban pollutants contribute to allergy has to be elucidated [corrected].

Economic evaluation of screening for prostate cancer: a randomized population based programme during a 10-year period in Sweden.

Prostate cancer is a growing health problem representing considerable costs. Screening and early curative treatment may reduce morbidity and possibly prevent future escalating costs. However, population screening programmes are generally not well accepted at present due to uncertainty about whether screening for prostate cancer can result in reduced mortality. Evidence from large, randomized, controlled trials is still lacking. The objective of this study was to calculate clinical and economic consequences of general prostate cancer screening based on a limited screening trial in a Swedish community and a decision-tree model. A random selection of 1492 men (50-69 years) were invited to repeated screening in 1987. They have been examined every third year (four rounds). The other 7679 men in the population act as controls. The results show that the total incremental health care costs for prostate cancer will increase by 179 million SEK per year with screening compared to no-screening. The number of detected cases of localized cancer will increase by about 1000, which represents an additional cost of about 158,000 SEK per case. In conclusion, general screening for prostate cancer can be performed with a reasonable cost per detected localized cancer. Information on the long-term effect on life quality and cancer mortality is unknown.

Parity among atopic and non-atopic mothers.

A temporary Th2 skewed immunity is essential for a successful outcome of pregnancy. It is also a hallmark of atopic disease. We recorded the number of siblings to 3667 children in relation to maternal atopy. In all, 65% of the allergic and 56% of the non-allergic mothers had more than one child (p < 0.001). These data support a hypothesis that the atopic genotype may be associated with an increased likelihood for a successful outcome of pregnancy and thus from an evolutionary point of view compensate for the less efficient host defence against microbial infections associated with this type of immunity.

Individuals living in areas with high background radon: a GIS method to identify populations at risk.

OBJECTIVE: to identify and link populations and individuals that live within high risk areas. DESIGN: census registers and disease registers which contain data on individuals can only give aggregate statistics relating to postal code districts, town, county or state boundaries. However environmental risk factors rarely, if ever, respect these man-made boundaries. What is needed is a method to rapidly identify individuals who may live within a described area or region and to further identify the disease(s) occurring among these individuals and/or in these areas. METHOD: this paper describes a method for linking the standard registers available in Sweden, notably the residence-property addresses they contain and the geographical coordinate setting of these, to map the population as a point coverage. Using standard GIS methods this coverage could be linked, merged or intersected with any other map to create new subsets of population. Representation of populations down to the individual level by automatised spatialisation of available census data is in its simplicity a new informatics method which in the designated GIS medium adds a new power of resolution. RESULTS: We demonstrate this using the radon maps provided by the local communes. The Swedish annual population registration records of 1991 for the county of Ostergötland and the property register available at the Central Statistical Bureau of Sweden formed the main data sources. By coupling the address in the population register to the property register each individual was mapped to the centroid of a property. By intersecting the population coverage with the radon maps, the population living in high, normal or low risk areas was identified and then analysed and stratified by commune, sex and age. The resulting tables can be linked to other database registers, to visualise and analyse geographical and related patterns. The methodology can be adapted for use with any other environmental map or small area. It can also be expanded to the fourth dimension by linking likewise available migration information to generate immediately coordinate-set, accumulated exposition and similar data.

Age-specific reference values for serum prostate-specific antigen in a community-based population of healthy Swedish men.

To establish normal reference values for prostate-specific antigen (PSA) in a Swedish population we investigated 878 healthy men, 56-75 years of age. They were randomly selected from a population of 9171 males in this group. Cancer of the prostate was excluded by digital rectal examination. When digital rectal examination was suspicious for carcinoma of the prostate and/or serum PSA > 4 micrograms l-1, fine-needle aspiration biopsy was performed. Central values, values of variance and reference limits were defined by a non-parametric method in four age groups. A strong positive correlation between PSA values and age was found and the variance increased with age. The relationship between PSA value and age was non-linear. For the age group 56-60 the upper reference limit (95th percentile) was 4.6 micrograms l-1 (confidence interval, CI: 3.9-5.5). For the age groups 61-65, 66-70 and 71-75 the corresponding values were 4.4 (3.8-5.2), 7.6 (6.5-8.9) and 8.4 micrograms l-1 (7.2-9.8) respectively. For the age groups studied the increment over time of the PSA value was 2-8% per year depending on age, with an average increment per year over 15 years of 4.3%. Overall, 11% of our reference sample had a serum PSA level > 4 micrograms l-1. We consider our study population to be representative for a normal Swedish male population in these age groups.

Logics and logistics of community intervention against osteoporosis: an evidence basis.

Under designations like small areas action research and intervention, directed 'ground-up' health promotion and prevention in the population form an important part of the ongoing medical systems development. There is recent evidence of the success of community intervention against cardiovascular disease. In osteoporosis, however, there is still a lack of conclusive data on both the logics and logistics of such an approach. Since 1988, a county health policy program has been formulated and implemented in Ostergötland, Sweden, following the principles and guidelines of the WHO HFA 2000 declaration. Vadstena (n approximately 7,600) was chosen for a local and generalizable osteoporosis prevention project mediated by the primary care organization by means of health promotion and education in the community. In the present report we emphasize that community intervention is an important new advancement of the medical systems, where the basic research questions include operational and management aspects as equally vital and measurable requisites and results as other performance and outcome variables. We found that a community intervention trial against osteoporosis is both motivated and feasible and in this report wish to provide evidence on these crucial issues of logics and logistics.

Bone mineral density in normal Swedish women.

We examined 429 women, aged 20-80 years, randomly selected from the population register to establish normal values for bone mineral density (BMD) in Swedish women. BMD of the spine and hip was measured by dual-energy X-ray absorptiometry (DEXA; Hologic QDR 1000) and in the forearm by single photon absorptiometry (SPA; Molsgaard ND-1100). The recalled age of menarche was negatively correlated to BMD at all ages. There was no significant change in BMD from 20-49 years at any site except a slight decline at Ward's triangle. Bone loss was rapid at all sites during the first decade after menopause. Thereafter, BMD declined slowly in the trochanter and total hip but more rapidly in the forearm, femoral neck, and Ward's triangle. BMD in the spine even increased in the eighth decade probably due to osteoarthritis. The average change in forearm BMD during the 15 perimenopausal years comprising mean age for menopause +/- 2 SD (43-57 years) was -0.4% per year in premenopausal females and -1.6% per year in postmenopausal females. The corresponding annual percental change was, for the spine, +0.2 and -1.7; neck, -0.7 and -1.7; trochanter, +0.5 and -1.5; and Ward's triangle, -0.1% and -2.2%, respectively. Our normal values for lumbar spine BMD prior to menopause did not differ from published values or the manufacturer's normal values; however, our spine BMD values for the first decade after menopause were significantly lower (approximately 10%) than in other studies. Our femoral neck BMD values for younger women were, like those of several other groups, significantly lower than the manufacturer's normal values, but our sample of young women in this study was small. The prevalence of osteoporosis, if defined as t score < -2.5 is highly dependent on the sampling of the reference population of young adult women, and also on the choice of skeletal site. Further studies on bone mineral density in healthy young adult women are needed.

Reversal of osteopenia with diet in adult coeliac disease.

To evaluate the effects of a gluten free diet on bone mineral density in untreated adult patients with coeliac disease, 63 patients (17-79 years, 35 women) were examined at diagnosis and after one year taking a gluten free diet. Bone mineral density was measured in the forearm using single photo absorptiometry and in the lumbar spine, femoral neck, and trochanter using dual energy x ray absorptiometry. The values for each patient were compared with those of 25 healthy controls, matched for sex, age, and menopausal state. Before being given a gluten free diet bone mineral density in the total group was reduced at all sites (p < 0.001). Age adjusted bone mineral density was inversely correlated with age. During the first year taking a gluten free diet bone mineral density increased at all sites (p < 0.01). This was seen in patients of all ages and in patients who were without symptoms of malabsorption (weight loss or diarrhoea) before treatment. Low bone mineral density in patients with untreated coeliac disease increases rapidly when treatment with a gluten free diet is followed. These findings emphasise the importance of early diagnosis and treatment in all patients with coeliac disease.

Distance from the Primary Health Center: a GIS method to study geographical access to health care.

Aerial distance from the dependent Primary Health Center is a crude but objective measure of geographical accessibility to Primary Health care facilities. This report describes a method for calculation of distances between the PHC and the population it serves using the data available from the local health authorities and the Swedish Central Statistical Bureau. The Swedish annual population registration records of 1991 and the property register available with the Central Statistical Bureau of Sweden formed the main data sources. By coupling the address in the population register to the property register each individual was mapped to the centroid of a property. The location of the PHCs as well as the areas covered by each were obtained from the local health authorities and mapped. By intersecting the population coverage with the PHC coverage the population for each PHC area was identified. Subsequently the distance to the PHC was calculated for each individual (property centroid). The population maps so generated can be linked to other databases to visualize and analyze the spatial dimension of health and disease. The methodology can be adapted for use with postal code districts, census enumeration tracts, or any other small area.

Bone mineral density in coeliac disease.

Patients with coeliac disease may have osteomalacia or osteoporosis, even in the absence of abdominal symptoms. Little is known about the effects of a gluten-free diet and villous restitution on the bone mineral density in adult patients with coeliac disease. Of the 288 patients with coeliac disease in our unit, 13 (5%) had persistent villous atrophy of the small bowel despite dietary recommendations over at least the previous 4 years. For each of these 13 patients, 1 or 2 controls with coeliac disease, matched for age, gender, menopausal state, and dermatitis herpetiformis, whose intestinal mucosa had normalized at least 4 years earlier, were identified (n = 17). Bone mineral density was measured in the forearm using single-photon absorptiometry and in the femoral neck and trochanter using dual-energy X-ray absorptiometry. Bone mineral density was reduced at all sites in patients with persistent villous atrophy compared with patients responsive to diet and healthy controls. Bone mineral density in patients responsive to diet did not differ from that in healthy controls. Persistent villous atrophy is associated with low bone mineral density, underlining the importance of keeping to a proper diet.