The issue of adverse health effects from dental amalgam and the concurrent low-dose exposure to inorganic mercury have been scrutinized by several Swedish expert groups during the past years. Only rarely have amalgam fillings in children been related to health effects. Experimental studies in genetically disposed animals have shown that low doses of inorganic mercury can induce autoimmune glomerulonephritis. The present case-control study included 31 children with acute glomerulonephritis and 33 with Henoch-Schönlein purpura retrieved from an in-patient register for the period 1973-1992 at the county hospital in Halmstad, Sweden. The median age was 10 and 9 years, respectively, for the two diagnostic groups. Dental clinics reported amalgam burden of the patients during the year before the date of diagnosis. Corresponding data were obtained for three randomly selected controls for each case, drawn from the case records of the same dental clinics, with matching for age and sex. Odds ratios (95% confidence interval) were 1.42 (0.49, 4.11) for Henoch-Schönlein purpura, 0.59 (0.25, 1.38) for acute glomerulonephritis and 0.84 (0.40, 1.75) for both diseases combined. The results of this study did not indicate increased disease risk in relation to amalgam burden.
BACKGROUND: The possible association between certain childhood infections and the propensity to develop allergic disease may include intestinal helminth infections. The experiences of such associations derive mainly from studies in tropical areas, and the results are not clear-cut. Objective: To explore the association between Enterobius vermicularis and allergic disease in Swedish children 4 to 10 years of age. METHOD: The occurrence of E. vermicularis was examined by perianal tape tests in 70 allergic children recovered from a pediatric register of positive skin-prick tests. A nonallergic control group (n = 102) was gathered from a cohort of children previously examined for the prevalence of E. vermicularis and allergic symptoms. RESULTS: In the allergic group 26 of the 70 cases (37%) had a positive tape-test for E. vermicularis, compared to 23 of the 102 cases (23%) in the nonallergic control group (p = .037). CONCLUSION: The results indicate that E. vermicularis could be more frequent in children with allergic disease as defined by allergic symptoms and a positive skin-prick test compared to nonallergic children, i. e., those without a history of allergic disease. These data, however, do not allow any conclusion on the nature of the possible association between E. vermicularis and allergic disease.
High-dose exposure to inorganic mercury in man can influence the immune system and in rare cases cause immune-related disease. Some experimental animals also react with autoimmunity after low doses of inorganic mercury. Glomerulonephritis and an increased formation of immunoglobulin type E (IgE) are characteristic of these reactions. A recent study of 15-year-old adolescents demonstrated an association between immunoglobulin type A (IgA) and mercury concentration in plasma (P-Hg). There was also an association between allergic disease and IgA levels. The present study included 54 male and 23 female 19-year-old students who were recruited from a cohort that had been previously defined in a survey of allergic disease. Of the students, 39 (51%) had asthma, allergic rhinoconjunctivitis or eczema. Similar amalgam burden and P-Hg levels were observed in students with (n = 39) and without (n = 38) allergic disease (P = 0.48 and P = 0.98, respectively). As expected, IgE levels were significantly higher in the group with allergic disease (P = 0.006), but there was no association between P-Hg and IgE. The P-Hg levels were very low (median 1.50 nmol/l) and correlated significantly (r = 0.31) with the small number of amalgam surfaces (P = 0.007). Thirty-seven students had no amalgam fillings. P-Hg levels did not associate significantly with IgA, but did so with IgG2 (r = 0.33; P = 0.003). No conclusive correlation was observed between IgG2 and amalgam fillings. The findings of this study in 19-year-old subjects differ from earlier data obtained in a sample 4 years younger. The possibility of chance in the association between P-Hg levels and IgG2 must, however, be considered.
OBJECTIVE--To study the association between allergic diseases (eczema, allergic rhino-conjunctivitis, and asthma), dental health, and the socioeconomic situation of Swedish teenagers. DESIGN--Cross-sectional survey with a questionnaire for allergic symptoms and parents' occupation (for socioeconomic classification); current dental status from the Public Dental Service. Bronchial reversibility test. Telephone inquiry of asthma cases. SETTING--Primary care and a school in the centre of a middle-sized Swedish town (approx. 80,000 inhabitants). PARTICIPANTS--137 pupils of both sexes, 13-15 years old. MAIN OUTCOME MEASURES--Number of reported cases with allergic disease and outcome of bronchial reversibility test in relation to social class. Number of validated cases of asthma. Number of filled tooth surfaces in healthy and diseased cases. RESULTS--Socioeconomic situation was found to associate with dental health, i.e. more fillings in lower social classes (P = 0.01), and with allergic disease, i.e. asthma and rhino-conjunctivitis (P = 0.05). Individuals from the upper social classes seemed prone to overreport asthmatic symptoms, whereas teenagers in the lower classes did the opposite, as indicated by five cases of pathologic values after bronchial reversibility tests in individuals who did not report asthmatic symptoms. CONCLUSION--The study indicates that socioeconomic situation associates significantly with both dental health and allergic disease. No association was found between dental health and allergic diseases.
The aim of the study was to explore the impact of birthplace and socio-economic characteristics on the risk of acute myocardial infarction (AMI) in a rural Swedish province. A case control study was performed and cases were all patients 30-72-y-old treated for the first time for an AMI during 1980-1992 and identified in a computerised hospital register. Three controls for each case were randomly selected from the national population register and were matched for gender, age and municipality. Birthplace ie within or outside the province, and a variety of socio-economic background factors were determined for cases and controls. The study comprised a total of 18 948 individuals including cases and controls.Altogether 4737 cases of AMI were identified whereof 3514 were men. Being born in the province was associated with the lowest risk for AMI in both sexes (RR=0.62, CI 0.57-0.67 for men and RR=0.61, CI 0.53-0.69 for women). A substantially reduced risk for men was found in farmers. In both sexes, high socio-economic status had a favourable effect on the risk to suffer an AMI. Being born in the province carried the lowest risk for AMI in both sexes and was independent of other tested socio-economic factors (income, education, occupation, and civil status). Province characteristics might be associated with this protective factor. Alternatively, migration as such might include unfavourable exposures that increase the risk for AMI among those who had moved to the province.
To estimate the prevalence of chronic regional and widespread musculoskeletal pain in a sample of the general adult population and study the association to age, sex, socioeconomic class, immigration, and housing area.
A cross sectional survey with a postal questionnaire to 3928 inhabitants on the west coast of Sweden.
The age and sex adjusted prevalence of chronic regional pain (CRP) was 23.9% and chronic widespread pain (CWP) 11.4% among 2425 subjects who responded to the complete questionnaire. Odds ratio (OR) for CWP showed a systematic increasing gradient with age and was highest in the age group 59-74 yrs (OR 6.36, 95% CI 3.85-10.50) vs age group 20-34 yrs. CWP was also associated with female sex (OR 1.91, 95% CI 1.41-2.61), being an immigrant (OR 1.83, 95% CI 1.22-2.77), living in a socially compromised housing area (OR 3.05, 95% CI 1.48-6.27), and being an assistant nonmanual lower level employee (OR 1.92, 95% CI 1.09-3.38) or manual worker (OR 2.72, 95% CI 1.65-4.49) vs being an intermediate/higher nonmanual employee. OR for CRP showed a systematic increasing gradient with age and was highest in the age group 59-74 yrs (OR 2.22, 95% CI 1.62-3.05) vs age group 20-34 yrs. CRP was also associated with being a manual worker (OR 1.63, 95% CI 1.19-2.23) vs being an intermediate/higher nonmanual employee.
Chronic musculoskeletal pain is common in the general population. Sociodemographic variables were overall more frequently and strongly associated with CWP than with CRP, which indicates different pathophysiology in the development or preservation of pain in the 2 groups.
Chronic exposure to inorganic mercury can cause kidney injury. Evidence gained from occupational medicine indicates that individuals who are exposed to only environmental sources, including amalgam tooth fillings, are at very little risk. Animal experiments, however, have revealed glomerular lesions of immunologic origin after low-dose exposure to inorganic mercury. In this study, the association between the number of amalgam tooth surfaces, urinary mercury, and proteinuria was explored in a sample of 48 randomly selected, apparently healthy male students who were 17-22 y of age. Presence of any of the following proteins in two separate urine samples was considered to be potentially indicative of any tubular and/or glomerular lesion: albumin, alpha-1-microglobulin (HC-protein), kappa and lambda light chains, and N-acetyl-beta-D-glucosaminidase. No significant relationship was found between any of the proteins and amalgam or urinary mercury. The results of this study did not suggest that amalgam fillings cause kidney dysfunction in humans.
Children with an autistic disorder may need more dental care and may also be more difficult to treat than healthy children. This study compared oral health in autistic and healthy children. Also explored was the dental management of autistic children within the non-specialized Public Dental Service. The study was designed as a case-control study with all cases of autistic disorders aged 3-19 years identified within a primary care area in southwest Sweden. One dentist did a clinical investigation of cases and one control per case. The patients, or their parents, answered a questionnaire. 28 patients were identified and 20 (71%) agreed to participate in the study. Cases and controls had a similar prevalence of fillings, caries, gingivitis and degree of oral hygiene. However, the need of orthodontic treatment seemed to be greater among the autistic children. According to a standardised assessment, autistic children were less able to cooperate in the dental treatment. Approximately 30% of the cases had occasionally been subjected to specialized dental care. The results of this study indicate that the care provided to autistic children within the non-specialized Public Dental Service is satisfactory, provided that there is access to a paediatric dentist when necessary.
OBJECTIVE--To study the association between allergic diseases (eczema, allergic rhino-conjunctivitis, and asthma) and different types of dental restorative materials (amalgam, composite, and glass ionomer) in Swedish schoolchildren. DESIGN--Cross-sectional survey with a questionnaire asking for symptoms of allergic disease during the previous year. This information was combined with current dental status (number and type of filled tooth surfaces). SETTING--Primary care and a school in the centre of a middle-sized Swedish town (approx. 80,000 inhabitants). PARTICIPANTS--348 pupils of both sexes 13-15 years old. OUTCOME MEASURES--The occurrence of allergic disease in pupils with and without dental fillings of different types. The mean number and type of filled tooth surfaces in diseased and healthy pupils. RESULTS--44% of the pupils had no amalgam fillings. This group of children reported significantly more often asthmatic symptoms than the group with amalgam (P = 0.02). The asthmatic children had a lower mean number of amalgam surfaces than the other pupils (P = 0.002) and also a lower mean number of filled tooth surfaces of all types. CONCLUSION--The results of this study do not support the theory that amalgam fillings increase the prevalence of allergic diseases or allergic reactivity as such in schoolchildren. Neither do composite and glass ionomer seem to cause such complications.
OBJECTIVE: To study the prevalence of Enterobius vermicularis and its association with finger sucking in young Swedish children. DESIGN: Cross-sectional survey with a questionnaire for symptoms of infestation with Enterobius vermicularis, and the children's habit of finger sucking (including fingernail biting). Perianal tape-test for identification of eggs of Enterobius vermicularis. SETTING: Primary care, day-care centres, and schools in a Swedish middle-sized town (approx. 80,000 inhabitants). PARTICIPANTS: 172 children of both sexes, 4-10 years old. MAIN OUTCOME MEASURES: The prevalence of Enterobius vermicularis and its association with finger sucking. RESULTS: 21% of the children were symptom-free carriers of Enterobius vermicularis, and finger sucking was strongly associated with a positive tape-test (p = 0.01). CONCLUSION: More children than previously known seemed to be symptom-free carriers of Enterobius vermicularis. Finger sucking should be considered when treating infested children and especially those with relapsing symptoms.