The relationship between interstitial lung abnormalities, mortality, and multimorbidity: a cohort study

BACKGROUND

Interstitial lung abnormalities (ILAs) are associated with increased mortality. It is unclear whether multimorbidity accounts for the mortality association or how strongly ILA is associated with mortality relative to other common age-associated diseases. We determined the association of ILA with all-cause mortality adjusted for multimorbidity, compared mortality associated with ILA and prevalent cardiovascular disease (CVD), diabetes mellitus, chronic kidney disease, chronic obstructive pulmonary disease and cancer and also determined the association between ILA and these diseases.

METHODS

We measured ILA (none, indeterminant, definite) using blinded reads of CT images, prevalent chronic diseases and potential confounders in two observational cohorts, the Framingham Heart Study (FHS) (n=2449) and Age, Gene/Environment Susceptibility - Reykjavik Study (AGES-Reykjavik) (n=5180). We determined associations with mortality using Cox proportional hazards models and between ILA and diseases with multinomial logistic regression.

RESULTS

Over a median (IQR) follow-up of 8.8 (1.4) years in FHS and 12.0 (7.7) years in AGES-Reykjavik, in adjusted models, ILAs were significantly associated with increased mortality (HR, 95% CI 1.95, 1.23 to 3.08, p=0.0042, in FHS; HR 1.60, 1.41 to 1.82, p<0.0001, in AGES-Reykjavik) adjusted for multimorbidity. In both cohorts, the association of ILA with mortality was of similar magnitude to the association of most other diseases. In adjusted models, ILAs were associated only with prevalent kidney disease (OR, 95% CI 1.90, 1.01 to 3.57, p=0.0452) in FHS and with prevalent CVD (OR 1.42, 1.12 to 1.81, p=0.0040) in AGES-Reykjavik.

CONCLUSIONS

ILAs were associated with mortality adjusted for multimorbidity and were similarly associated with increased mortality compared with several common chronic diseases. ILAs were not consistently associated with the prevalence of these diseases themselves.

Prothrombin Determination by Means of a Chromogenic Peptide Substrate

A two stage method to determine prothrombin with the chromogenic peptide substrate benzoyl-phe-val-arg-p-nitroanilide has been worked out. Citrated plasma (10 μl) was diluted in 600 μl tris buffer, pH 8.2, ionic strength 0.18 and activated with 250 μl of a commercial rabbit brain-lung thromboplastin. After 325 s incubation at 37° C 200 μl of a 1 mM solution of the chromogenic substrate was added and the increase in absorbance was recorded in a LKB-Beckman 8600 enzyme analyzer. A reading time of 1 minute (including a delay of 20 s) was used which permitted 55 analyses per hour to be carried out. An approximate linear relationship was found between ΔA/min and dilutions of normal plasma in prothrombin deficient plasma. The method is insensitive to variations of factors V, VII and X. Less than 10 % of normal plasma was needed to “normalize” plasmas deficient in factor V or VII or X.

A group of 99 dicoumarol treated patients and 23 normal subjects has been investigated using the present method and compared with a factor II-VII-X determination method. A correlation coefficient of 0.95 was found.

Application of Indicators, Predictors and Diagnostic Indices in Coagulation Disorders

A theoretical model for the evaluation of binary and continuous diagnostic variables by indicators and predictors was recently described by Sebag and Hall [5]. The application of the new method for the evaluation of a self-administered questionnaire was described by Wahlberg et al. [6, 7]. In the present study the model is applied to material from two clinical tests :

1. Three blood coagulation laboratory tests for the diagnosis of von Willebrand’s disease (continuous variables) ;

2. Six blood coagulation laboratory tests performed in healthy males, aged 40, from Edinburgh and Stockholm, for the evaluation of risk factors in ischemic heart disease (continuous variables).

The diagnostic power of the laboratory variables is calculated by indicators and predictors. The total diagnostic capacity of all variables is expressed by a laboratory or summation index.

The material from the coagulation tests shows that it was possible to separate healthy individuals from diseased ones. By laboratory indices calculated for six coagulation variables, the Stockholm and Edinburgh populations were found to have different blood coagulation patterns.

Application of Indicators, Predictors and Diagnostic Indices in Coagulation Disorders

A recently described theoretical model for the evaluation of binary and continuous diagnostic variables by indicators and predictors, is in the present study applied to a self-administered-questionnaire for obtaining a medical history of different blood coagulation disturbanoies (binary variables).

The diagnostic power of each question is calculated by indicators and predictors. The total diagnostic capacity of the questionnaire is expressed by an anamnestic or summation index.

The questionnaire was shown to be able to separate healthy individuals from diseased ones. A rank order of the diagnostic capacity of the questions, built upon indicators and predictors, is presented.

Residential radon and lung cancer among never-smokers in Sweden

In this study, we attempted to reduce existing uncertainty about the relative risk of lung cancer from residential radon exposure among never-smokers. Comprehensive measurements of domestic radon were performed for 258 never-smoking lung cancer cases and 487 never-smoking controls from five Swedish case-control studies. With additional never-smokers from a previous case-control study of lung cancer and residential radon exposure in Sweden, a total of 436 never-smoking lung cancer cases diagnosed in Sweden between 1980 and 1995 and 1,649 never-smoking controls were included. The relative risks (with 95% confidence intervals in parentheses) of lung cancer in relation to categories of time-weighted average domestic radon concentration during three decades, delimited by cutpoints at 50, 80, and 140 Bq m(-3), were 1.08 (0.8--1.5), 1.18 (0.9--1.6), and 1.44 (1.0--2.1), respectively, with average radon concentrations below 50 Bq m(-3) used as reference category and with adjustment for other risk factors. The data suggested that among never-smokers residential radon exposure may be more harmful for those exposed to environmental tobacco smoke. Overall, an excess relative risk of 10% per 100 Bq m(-3) average radon concentration was estimated, which is similar to the summary effect estimate for all subjects in the main residential radon studies to date.

Solvent use and time to pregnancy among female personnel in biomedical laboratories in Sweden

OBJECTIVES

To elucidate possible effects on fecundability from chemical, biological, and physical agents in laboratories, a retrospective study based on a questionnaire was conducted among female personnel who worked in Swedish biomedical research laboratories. Female personnel in non-laboratory departments were used as a reference group. The maximum number of women included in the analyses was 560. This corresponded to 2519 menstrual cycles. These women had given birth at least once during the period 1990-4.

METHODS

Time to pregnancy was used to estimate the fecundability-that is, probability of conception of a clinically detectable pregnancy per cycle. The fecundability ratio (FR) between exposed and unexposed cycles was calculated with a discrete time analogue of the Cox's proportional-hazards model. The FR estimates below unity indicate subfecundity.

RESULTS

Work with organic solvents in general in laboratory work, gave a decreased adjusted fecundability ratio (FR) of 0.79 (95% confidence interval (95 % CI) 0.68 to 0.93). Moreover, work with acetone and use of viruses also showed decreased FRs, 0.72 (0.53 to 0.97) and 0.66 (0.49 to 0.90), respectively.

CONCLUSIONS

The results of the present study give some indications of reduced fecundability for work with specific agents in laboratories, and support previously reported findings of a negative influence of organic solvents on fecundity among female laboratory personnel.

Carpal tunnel syndrome with severe sensory deficit: endoscopic release in 18 cases

Carpal tunnel syndrome (CTS) with severe sensory deficit was treated with endoscopic carpal tunnel release in 18 hands of 16 consecutive patients (median age 72 (28-92) years). In all hands, preoperative 2-point discrimination (2-PD) exceeded 15 mm in the radial and ulnar sides of the pulps of at least 2 of the 3 radial digits. All patients underwent an independent evaluation and answered a questionnaire concerning 11 activities of daily living (ADL) preoperatively and 6 months postoperatively. Complete resolution or improvement in daytime numbness and tingling was reported in 12 of 17 hands, of night symptoms in 12 of 16 hands, and of pain in 10 of 11 hands. The median ADL score improved from 3.1 to 1.4 (on a 1- to 5-point scale). 13 of the 16 patients were satisfied with the outcome. Two-PD had normalized in 14 hands and improved in 2. The results indicate that endoscopic carpal tunnel release is effective in improving symptoms and function in patients with CTS and severe sensory deficit, and that the prognosis for sensory recovery is good.

Magnesium in drinking water in relation to morbidity and mortality from acute myocardial infarction

We investigated the importance of magnesium and calcium in drinking water in relation to morbidity and mortality from acute myocardial infarction. Cases were men and women 50-74 years of age living in 18 Swedish municipalities who had suffered an acute myocardial infarction some time between October 1, 1994, and June 30, 1996. Controls were randomly selected from the same study base. We interviewed the surviving cases (N = 823) and controls (N = 853), focusing on risk factors for acute myocardial infarction. We collected individual data on drinking water levels of magnesium and calcium. We classified subjects by quartile of water magnesium or calcium levels. The total number of cases was similar in the four quartiles. The risk of death was 7.6% (95% confidence interval = 2.1-13.1) lower in the quartile with high magnesium levels (> or = 8.3 mg/liter). The odds ratio for death from acute myocardial infarction in relation to water magnesium was 0.64 (95% confidence interval = 0.42-0.97) for the highest quartile relative to the three lower ones. Multivariate analyses showed that other risk factors were not important confounders. For calcium, this study was inconclusive. The data suggest that magnesium in drinking water is associated with lower mortality from acute myocardial infarction, but not with the total incidence.

Pregnancy outcome of personnel in Swedish biomedical research laboratories

Possible hazardous effects of laboratory work on the reproduction outcomes of female laboratory personnel in Sweden from 1990 to 1994 were investigated in a questionnaire-based study (n = 1052) by comparison with personnel in non-laboratory departments. The individual woman constituted the primary sampling unit, with her pregnancies defined as the unit of analysis. Allowance for dependence between different pregnancies of the same woman was considered by applying random effect models. With regard to spontaneous abortions, no elevated odds ratio was found for laboratory work in general, but an odds ratio of 2.3 and a 95% confidence interval of 0.9 to 5.9 (n = 856) was connected to working with chloroform. The odds ratio for large for gestational age infants in association with the mother's laboratory work was 1.9 (confidence interval, 0.7 to 5.2). The result with regard to spontaneous abortion partly supports previously reported increased risks of miscarriage related to laboratory work with solvents.

The association of shift work and nitrous oxide exposure in pregnancy with birth weight and gestational age

We examined the relation between shift work and occupational nitrous oxide exposure in the second trimester of pregnancy and birth weight and gestational age at delivery among the members of the Swedish Midwives Association. Eighty-four per cent of members who were registered in 1989 responded to a postal questionnaire concerning occupational exposures, including work schedule and the use of nitrous oxide, in relation to each of their pregnancies. We obtained information on births from the Swedish Medical Birth Register. We used models with allowance for dependence between births for the same woman and found that night work was associated with preterm birth (<37 weeks) [odds ratio (OR) = 5.6; 95% confidence limits (CL) = 1.9, 16.4] and to a lesser extent with low birth weight [OR = 1.9 (95% CL = 0.6, 5.8)]. Three-shift work schedule (day, evening, and night rotation) showed a possible association with preterm birth [OR = 2.3 (95% CL = 0.7, 7.3)]. Exposure to nitrous oxide use was associated with reduced birth weight (-77 gm; 95% CL = -129, -24) and an increase in the odds of infants being small for gestational age (< or = 10th percentile of weight for gestational week) (OR = 1.8; 95% CL = 1.1, 2.8).

Mortality and cancer incidence in biomedical laboratory personnel in Sweden

BACKGROUND

The work in biomedical laboratories is associated with exposure to a mixture of known and potential chemical carcinogens, mutagens, and teratogens. Previous studies have suggested an excess of brain tumors and hematopoietic system malignancies as well as breast cancers in women.

METHODS

This retrospective cohort study investigated the standardized mortality ratio (SMR) and the standardized incidence ratio (SIR) for cancer in biomedical research laboratory personnel in Swedish universities 1970-1992. The cohort comprised 5,035 laboratory and, as an internal reference group, 2,923 nonlaboratory employees.

RESULTS

The overall death rate was lower in both groups than in the general population. The SIR for brain tumors among male laboratory workers was 1.69 (0.62-3.68) and among male laboratory scientists, after more than 10 years of work (4 cases), it was 3.11 (0.85-7.56). There was an elevated SIR for malignant melanoma among female scientists in laboratories (3.51, 0.96-8.98) and for male scientists in nonlaboratory departments (2.86, 1.05-6.22). The SIR for breast cancer among female laboratory scientists was 1.62 (0.78-2.98).

CONCLUSIONS

The present findings lend some support to an excess of brain tumors among male scientists and of breast cancer in female scientists in biomedical research laboratories.

[Pediatric tonsillectomy can be performed as day surgery]

In the spring of 1996, tonsillectomy, traditionally regarded as a procedure requiring hospitalization, began to be performed at the recently started day surgery unit at Danderyd Hospital. The article consists in a report of results obtained with a series comprising just over 200 children who were the first to undergo adenotonsillectomy in day surgery, and followed up, for instance, by questionnaire. There were no cases of complications requiring hospitalization during the first postoperative day. The parents were fairly satisfied with the care provided, though 25 per cent of them said that in the event of a new operation being necessary they would prefer that it be performed as an in-patient procedure.

Magnesium and calcium in drinking water and death from acute myocardial infarction in women

A relation between water hardness and cardiovascular death has been shown in previous studies. In this case-control study, we investigated the levels of magnesium and calcium in drinking water and death from acute myocardial infarction among women. The study population encompassed 16 municipalities in southern Sweden. Cases were women who had died from acute myocardial infarction between the ages of 50 and 69 years during 1982-1993 (N = 378), and controls were women who had died from cancer (N = 1,368). We obtained magnesium and calcium concentrations of the individual water sources. We divided the subjects into quartiles and found that odds ratios (ORs) were lower at higher levels of both magnesium and calcium. For the quartile with the highest magnesium levels (> or =9.9 mg/liter), the OR adjusted for age and calcium was 0.70 (95% confidence interval = 0.50-0.99). For calcium, the adjusted OR for the quartile with the highest level (> or =70 mg/liter) was 0.66 (95% confidence interval = 0.47-0.94). The results suggest that magnesium and calcium in drinking water are important protective factors for death from acute myocardial infarction among women.

Magnesium in drinking water and body magnesium status measured using an oral loading test

Epidemiological studies have shown an inverse relationship between magnesium in drinking water and death from ischaemic heart disease. The question is whether magnesium in drinking water can be critical for the body magnesium status. The aim of this study was to investigate, using an oral loading test, whether a change in body magnesium status could be found among people who change from drinking water with a low magnesium concentration to water with higher concentrations. The subjects participating in the study were 9 men and 3 women 65-70 years old, living in the city of Göteborg, Sweden, where the magnesium concentration in the tap water is low (1.6 mg/l). Drinking water was prepared with 200 mg MgCl2 x 6H2O added per litre to a level of 25 mg/l, and was distributed to the subjects twice a week for 6 weeks. Excretion of magnesium, potassium and creatinine, basal and after oral magnesium loading (tablets containing 575 mg), was measured in 24 h urine before and after the supplementation period. Calculations were made for the total excretion (mmol/24 h), and in relation to creatinine. The subjects' intake of magnesium via food and water was estimated using a questionnaire. There was a difference between the post load excretion of magnesium, expressed as the magnesium/creatinine ratio, before and after the supplementation period. The mean percentage change was a 14.6% (p=0.047) increase. No changes were found for potassium. In summary, the results indicate that magnesium in drinking water can affect body magnesium status.

Osteotomy versus tendon arthroplasty in trapeziometacarpal arthrosis: 17 patients followed for 1 year

We evaluated 2 consecutive cohorts of patients with primary trapeziometacarpal arthrosis 1 year after either first metacarpal osteotomy or trapezial excision with abductor pollicis longus tendon arthroplasty. At follow-up, 4 of 7 patients treated with osteotomy had pain at rest and/or with light activities and were dissatisfied with the results of surgery, all 4 had advanced (stage III) preoperative trapeziometacarpal arthrosis. 1 of 10 patients (5 having stage III arthrosis) treated with abductor pollicis longus arthroplasty had pain with light activities, and no patient was dissatisfied. Our findings indicate that first metacarpal osteotomy as a surgical option in trapeziometacarpal arthrosis should be limited to patients with early disease.

Extensor carpi radialis longus tendon arthroplasty in the treatment of primary trapeziometacarpal arthrosis

A prospective study was conducted to evaluate patient outcomes following trapezial excision and extensor carpi radialis longus tendon arthroplasty in primary trapeziometacarpal arthrosis. Seventeen patients were evaluated both preoperatively and postoperatively at both 12 months and at final follow-up examination at a mean of 39 months (range, 20-56 months). Surgery resulted in complete or significant pain relief and satisfaction with outcome for 16 patients as evaluated at final follow-up examination. Patients with a longer history of thumb pain and more advanced preoperative radiographic changes were more likely to have residual pain after surgery. The mean preoperative activities of daily living (ADL) scores improved significantly. The mean pulp and key pinch strength were 93% and 100%, respectively, of the preoperative values but were significantly lower than the mean pinch strengths recorded in an age-matched control population. Substantial proximal migration of the first metacarpal during maximal pinch was noted in 4 patients who still had some degree of thumb pain with light work. Scaphotrapezoid arthrosis had no correlation to postoperative residual pain.

Pet birds and risk of lung cancer in Sweden: a case-control study

OBJECTIVE

To investigate the association between keeping birds and the risk of lung cancer in Sweden.

DESIGN

Case control study based on cases of lung cancer and community controls. Interviews were performed by two nurses specially trained for this project.

SETTING

Three major referral hospitals located in southwest Sweden.

SUBJECTS

All patients aged 75 and under with newly diagnosed lung cancer and of Scandinavian birth who lived in one of 26 municipalities in Gothenburg and Bohus county or Alvsborg county. Potential control subjects matched on county of residence, sex, and closest date of birth were selected from population registries. In the context of a larger case-control study, information on pet birds was obtained from 380 patients with lung cancer (252 men) and 696 controls (433 men).

MAIN OUTCOME MEASURES

Odds ratios for lung cancer in relation to whether or not pet birds were kept and the duration of keeping pet birds.

RESULTS

The adjusted odds ratio for ever versus never exposed to pet birds at home was 0.94 (95% confidence interval 0.64 to 1.39) for men and 1.10 (0.64 to 1.90) for women. There was no evidence of a trend for increased risk of lung cancer with duration of bird ownership.

CONCLUSION

Bird keeping does not seem to confer any excess risk of lung cancer to Swedish men or women.

Shift work, nitrous oxide exposure and subfertility among Swedish midwives

BACKGROUND

Shift work and nitrous oxide exposure have both been suspected of having adverse influence on the reproductive performance of health workers. Time to pregnancy has been suggested as a sensitive measure of fecundity in occupationally exposed groups. We investigated the effects of shift work and nitrous oxide exposure on the fertility of Swedish midwives.

METHODS

A questionnaire was mailed to all members of the Swedish Midwives Association who were born 1940 or thereafter, 3985 in all. Eighty-four per cent responded. Detailed information on the number of menstrual cycles required to achieve pregnancy and the working conditions during that period were obtained concerning the most recent, planned pregnancy occurring after 1983. The per cycle probability of becoming pregnant was calculated for each exposure category, and the relation to the unexposed was expressed as fecundability ratios.

RESULTS

Midwives who worked two-shift, three-shift rotas, or only nights had reduced fertility compared to those working in the day time. The fecundability ratios were 0.78 (95% confidence interval [CI]: 0.65-0.94), 0.77 (95% CI: 0.60-0.98), and 0.82 (95% CI: 0.64-1.03), respectively, after adjustment for covariates. No effect of nitrous oxide exposure was noted except in the small group reporting that they assisted at more than 30 deliveries per month when nitrous oxide was used (fecundability ratio = 0.64; 95% CI: 0.44-0.95).

CONCLUSION

Shift work and frequent, high occupational exposure to nitrous oxide may have a negative influence on the ability of women to become pregnant.

Shift work, nitrous oxide exposure, and spontaneous abortion among Swedish midwives

OBJECTIVES

To study the relation between irregular work hours, nitrous oxide (N2O) exposure, and the risk of spontaneous abortion.

METHODS

All 3985 female members of the Swedish Midwives Association in 1989, born in 1940 or later, received a questionnaire on exposure before and during all of their pregnancies. Questions on work conditions covered occupation, extent of employment, workplace, work schedules, use of anaesthetics, and work load. The association between exposure variables and spontaneous abortion was analysed by logistic regression models.

RESULTS

Night work and three shift schedules among midwives showed increased odds ratios (ORs) (95% confidence intervals (95% CI)) 1.63 (0.95-2.81) and 1.49 (0.86-2.59), respectively. The ORs of late spontaneous abortions (after the 12th week of pregnancy) was increased for night work 3.33 (1.13-9.87). Use of N2O (> 50% of the deliveries) was not associated with increased risk of spontaneous abortion OR 0.95 (0.62-1.47). Frequent or permanent shortage of staff was related to an increased risk of spontaneous abortions before the 13th week of pregnancy.

CONCLUSIONS

The results support the hypothesis that night work and high work load increase the risk of spontaneous abortion.

Magnesium in drinking water and death from acute myocardial infarction

The relation between death from acute myocardial infarction and the level of magnesium in drinking water was examined using mortality registers and a case-control design. The study area comprised 17 municipalities in the southern part of Sweden that have different magnesium levels in the drinking water. Cases were men in the area who had died of acute myocardial infarction between ages 50 and 69 years during the period 1982-1989 (n = 854). The controls were men of the same age in the same area who had died from cancer during the same time period (n = 989). In both groups, only men who consumed water supplied from municipal waterworks were included in the study. The subjects were divided into quartiles according to the drinking water levels of magnesium and calcium and the quotient between magnesium and calcium. The odds ratios for death from acute myocardial infarction in the groups were inversely related to the amount of magnesium in drinking water. For the group with the highest levels of magnesium in drinking water, the odds ratio adjusted for age and calcium level was 0.65 (95 percent confidence interval 0.50-0.84). There was no such relation for calcium. For the magnesium/calcium quotient, the odds ratio was lower only for the group with the highest quotient. These data suggest that magnesium in drinking water is a important protective factor for death from acute myocardial infarction among males.

Lung cancer, smoking and diet among Swedish men

In a prospective case-control lung cancer study in the west of Sweden, the relationship between lung cancer, smoking and dietary factors was investigated. Suspected cases were collected from pulmonary units at two central hospitals in the area investigated and population controls of the same age and sex were selected from registers. The majority of cases and controls were interviewed by specially trained nurses, using a food frequency questionnaire. The lung cancer diagnosis (ICD 7, 162.1) was made using data from the local cancer register. In an analysis based on 308 cases and 504 controls, a dose-related increase in lung cancer risk for smokers was found, although no significant risk was found for males smoking 1-10 cigarettes/day for less than 20 years. A lower consumption of vegetables was related to a higher risk, both for smokers and nonsmokers. A higher consumption of milk was related to an increased risk.

Dietary factors and lung cancer among men in west Sweden

BACKGROUND

Previous studies have reported an association between tea drinking and lung cancer. In view of these data, the relationship between tea drinking as well as other dietary factors and lung cancer was investigated in a case-control study in the west of Sweden.

METHODS

Patients with suspected lung cancer were collected from pulmonary units at central hospitals in the area investigated, and population controls were matched for age. The material reported here comprises 308 male cases with a confirmed diagnosis of lung cancer and 504 controls. The participants were interviewed by specially trained nurses, using a questionnaire to assess smoking, dietary habits, occupational exposures and conditions in the residential area (local air pollution). This paper reports the results from dietary factors studied with a food frequency technique.

RESULTS

The results demonstrated a strong protective effect of vegetables (odds ratio [OR] = 0.69, 95% confidence interval [CI]: 0.46-1.05, and OR = 0.37, 95% CI: 0.23-0.61 for intermediate and high consumption classes respectively). A low OR was consistent for all histological types of lung cancer. High consumption of fruits did not show any similar protective effect. Drinking milk was associated with a dose-response related risk increase after adjustment for smoking and vegetable consumption (P for trend = 0.07). Odds ratio was 1.73, 95% CI: 1.00-3.01 for high consumption of milk.

CONCLUSIONS

High intake of vegetables had a strong protective effect among males. Diet is thus a potential confounding factor in studies on lung cancer and environmental factors and should thus be taken into consideration in the planning of such studies.

Comparison of oral health data from self-administered questionnaire and clinical examination

In order to assess the validity of self-reported oral health data 319 subjects randomly selected from the respondents to an oral health survey were examined clinically. The level of agreement between the two methods of examination was estimated by the kappa statistic. Substantial agreement (kappa = 0.65) was found between the reported and observed number of remaining teeth and the difference between underreporting and overreporting was small. The results indicate that valid data for planning purposes and for monitoring changes in such oral health indicators as the proportion of individuals having 28 or more teeth, the proportion of subjects having a minimum of 20 functional teeth, the level of edentulousness and the presence of complete and partial dentures, can be obtained from postal questionnaires.

Edentulousness in Iceland in 1990. A national questionnaire survey

Levels of edentulousness were established for seven age groups by means of self-administered questionnaires. The percentage of edentulousness in the Icelandic adult population (18 years and over) was 20.7%. Edentulousness was first reported in the 35- to 44-year-olds and increased rapidly with age. Women had a higher level of edentulousness than men, and the percentage of edentulous people in Reykjavík was significantly lower than in towns, villages, and rural areas. The proportion of edentulous 35- to 44-year-olds and those 65 years old or older was significantly lower than in a similar study in 1985. The percentage of 18- to 79-year-old edentulous Icelanders in 1990 decreased considerably from the results of a national survey on oral health performed in 1962, mainly as a result of a major reduction of edentulousness in the younger age groups and among women.

Reduced mite allergen levels in dwellings with mechanical exhaust and supply ventilation

Seventy similar bungalows constructed between 1968 and 1970 in the same suburban area of Stockholm were investigated regarding the content of house dust mite allergen, absolute indoor humidity, type of ventilation and basement construction. Houses with mechanical exhaust and supply ventilation had an indoor humidity above 7 g/kg less often than houses without this type of ventilation (Odds ratio 0.1, 95% confidence interval 0.0-0.2). Furthermore, only five of the 24 houses with exhaust and supply ventilation contained mattress dust mite allergen concentrations exceeding the median value (98.5 ng/g) compared with 30 of 46 hours which did not have such ventilation (odds ratio = 0.1, C.I. 0.0-0.5). Houses with both natural ventilation and crawl space basement harboured significantly less mattress mite allergen than houses having the same type of ventilation, but with a concrete slab basement. In a cold temperature climate, type of building construction and ventilation seem to be important for the occurrence of house dust mite allergens in dwellings. Our results indicate that modern energy-efficient houses should be equipped with mechanical exhaust and supply ventilation to reduce indoor air humidity during the dry winter months and the risk of mite infestation.

Serum C-reactive protein in the differential diagnosis of acute meningitis

The ability of serum C-reactive protein (S-CRP) to differentiate between acute bacterial and viral meningitis was evaluated in 235 patients, both children and adults. The patients underwent lumbar puncture due to suspected central nervous system (CNS) infection. In patients with bacterial meningitis, 7/60 (12%) had S-CRP concentrations below 50 mg/l. Of these patients, 4 were children below 6 years of age, all with symptoms of meningitis for less than 12 h before admission and 3 adults of whom 1 had symptoms of meningitis for less than 12 h. In patients with viral meningitis, 15/146 (10%) had S-CRP concentrations above 50 mg/l. Only 3 children below 6 years of age with viral meningitis had S-CRP concentration above 20 mg/l, but none exceeded 50 mg/l. An S-CRP value above 50 mg/l in patients with CSF pleocytosis usually indicates bacterial etiology. However, S-CRP values above 50 mg/l may occasionally be seen in viral meningitis. In children younger than 6 years of age a discriminatory level for S-CRP of 20 mg/l can be used to distinguish between bacterial and viral meningitis, but for older patients a discriminatory level of 50 mg/l is more appropriate. If the duration of the illness is less than 12 h, S-CRP concentrations below the discriminatory levels are of limited diagnostic value.

Use of questionnaires in a study of spontaneous abortion in a general population

STUDY OBJECTIVE

The aim was to evaluate the appropriateness of postal questionnaires in studies of spontaneous abortion in a general population.

DESIGN

Survey of spontaneous abortions by comparing diagnoses reported in questionnaires to information collected from hospital records and a discharge register.

SETTING

The study took place in the general community.

PARTICIPANTS

The study involved a random sample of 1400 women born between 1935 and 1960, living in two towns in the south west of Sweden.

MEASUREMENTS AND MAIN RESULTS

9% of spontaneous abortions among respondents were not reported in the questionnaire, and 31% were missing in the register; 80% of the spontaneous abortions reported in the questionnaire could be verified in hospital records, and a further 7% were mentioned in the records but not certified by a doctor; 97% of the diagnoses received by the women who had answered affirmatively to two complementary questions on spontaneous abortions could be found in the records.

CONCLUSIONS

Postal questionnaires can be used in epidemiological studies of spontaneous abortions, among a general population as well as among occupational groups.

Outcome of pregnancy in relation to irregular and inconvenient work schedules

The relation between irregular and inconvenient working hours and the outcome of pregnancy was studied among women employed at a hospital in Sweden some time between 1980 and 1984. A questionnaire was distributed to 807 women; 81% replied. The pregnancies were divided into six groups with respect to work schedules during pregnancy. A slightly, but not significantly, increased risk of miscarriage was found in women who worked irregular hours or rotating shifts compared with women who worked only during the day (RR = 1.44, 95% confidence interval 0.83-2.51). Infants of non-smoking mothers who worked irregular hours had significantly lower birth weights than infants of non-smoking women working day time only. This difference was largest at birth order 2+. Similar results were found for infants of this birth order whose non-smoking mothers worked evenings or rotating shift.

Outcome of pregnancy in women engaged in laboratory work at a petrochemical plant

The aim of the investigation was to study whether laboratory work or other types of chemical work at one petrochemical plant were associated with an increased risk for miscarriage or reduced birthweight. The study was based on questionnaire data for 95% of the women working at the plant between 1973 and 1987. A statistically significant difference between observed and expected number of miscarriages (p less than 0.05) was seen during the period 1970-1974 among women working in one of the laboratories during the first trimester. No suspicions could be raised against any specific chemical as a cause of the unsuccessful pregnancies. The results do not indicate the presence of an increased risk today.

Value of cerebrospinal fluid analysis in the differential diagnosis of meningitis: a study in 710 patients with suspected central nervous system infection

A prospective study to determine the value of cerebrospinal fluid analysis in the differential diagnosis of meningitis was performed in 710 consecutively observed patients, both children and adults, who underwent lumbar puncture due to suspected central nervous system infection. Diagnoses included acute or presumed bacterial meningitis (n = 79), acute or presumed viral meningoencephalitis (n = 218), acute unclassified meningitis (n = 6), other infections of the central nervous system (n = 37), non-infectious neurological diseases (n = 76) and control patients (n = 294). The sensitivity, specificity and predictive values were determined for cerebrospinal fluid white blood cell count, total protein, lactate, glucose and C-reactive protein levels as well as the blood/cerebrospinal fluid glucose ratio. Determination of cerebrospinal fluid levels of lactate (greater than or equal to 3.5 mmol/l) was found to be superior to the other tests. The C-reactive protein level gave no additional diagnostic information when the lactate level was determined. The white blood cell count, and total protein and glucose levels were often unreliable tools for differential diagnosis, largely due to low sensitivity at realistic discriminatory limits. The study confirms that no cerebrospinal fluid test is fully reliable in distinguishing bacterial meningitis from other forms of meningitis.

Outcome of pregnancy among women living near petrochemical industries in Sweden

The association between exposure to emissions from petrochemical industries and outcome of pregnancy was examined in a small area of Sweden. The study was based largely, but not entirely, on questionnaire data and evaluated the pregnancies which occurred between the end of 1963 and 30 June 1981 for a sample of 1400 women born between 1935 and 1960. In addition to the questionnaire study, information on all infants born between 1973 and 1981 in this area was obtained from central registers. The miscarriage rate was slightly elevated in the exposed area (OR = 1.15, 0.75-1.76, 95% confidence interval). While a statistically significant increase in miscarriages was found for a small subset of women who worked for one of the petrochemical companies during pregnancy (OR = 6.6, 2.3-19.2), the overall results did not support the hypothesis that ambient community exposures were associated with an increased risk of unfavourable pregnancy outcome.

Orthopantomographic examination of the edentulous mouth

Orthopantomograms from 250 persons, edentulous in one or both jaws, were examined with the aim to assess the frequency and location of significant radiographic abnormalities. The most frequent findings were retained roots and teeth, disclosed in 11.1% and 4.9% of the subjects, respectively. The findings were compared with the results of previous surveys and the various radiographic methods used in the examination of edentulous jaws discussed. The results of this and previous studies demonstrates (1) the necessity of a routine radiographic examination of the jaws of every patient before construction of a single denture or complete dentures, and (2) the need for a better extraction technique together with more universal use of radiographs before and after extraction.

Chylothorax as a complication after delivery

A 23-year old female who developed a chylothorax as a probable complication after delivery is described and a possible mechanism is proposed. Conservative treatment was unsuccessful and the surgical management was complicated by an anatomical variation with the thoracic duct presenting as a plexiform system instead of a single duct.

Discomfort from rubber gloves indicating contact urticaria

Rubber glove intolerance is a common dermatological problem and hypersensitivity of both delayed and immediate types occur. In order to study immediate skin reactions induced by rubber gloves, 15 patients with discomfort and itch produced by rubber gloves were examined. The patients were provoked by wearing rubber gloves, scratch tested with gloves, rubber chemicals and powders. RAST-tests were performed using an extract from the rubber tree (Hevea brasiliensis). In 6/15 patients, contact urticaria was confirmed, in 3 of whom IgE antibodies to latex were demonstrated.

Pleuropulmonary reactions in patients on bromocriptine treatment

Pleural thickening was observed in 4 patients during treatment with bromocriptine in dosages of 10-90 mg/day. Three patients who received at least 50 mg/day developed respiratory symptoms, elevated ESR and pleural effusion, which were normalized after withdrawal of the drug or reduction of the dosage. However, the pleural thickening was not fully reversible in any of the patients.

Allergy to weeping fig--a new occupational disease

During the last decade green plants have become more common in interior decoration. There are companies specializing in the leasing of green plants to public buildings and offices. Weeping fig is one of the most popular green plants. Dust and dry components of the plant are usually removed by vigorous shaking. In this way the allergen becomes airborne. During a few months we have seen several plant keepers who have developed airway allergy to weeping fig. Two of them have been thoroughly investigated. Both are atopics. Extracts were made from leaves and branches and both patients had positive skin prick tests and RAST. The risk of sensitization in plant keepers who work with weeping fig is probably considerable.

Torus palatinus in Icelandic schoolchildren

Three populations in South- and North-Thingeyjarsýslas, Northeast Iceland, were surveyed for the presence of torus palatinus. A total of 987 schoolchildren (489 male and 487 female) were examined. A statistically significant difference was noted between the prevalence in South-Thingeyjarsýsla (33.3%) and North-Thingeyjarsýsla (14.6%). Prevalence and size were affected by age and population but not by sex. An association between torus palatinus and torus mandibularis was not found. Secular changes in the occurrence of torus palatinus in Icelanders emphasize the importance of environmental etiological factors and diminish the value of torus palatinus as a racial trait.

Crown size of deciduous teeth in Icelanders

Mesiodistal and buccolingual crown diameters of deciduous teeth were measured from dental casts of 540 Icelandic children. Statistically significant sexual dimorphism was present in five of the buccolingual and in six of the mesiodistal diameters. The variability of the measurements followed the field concept but did not show systematic sexual dimorphism. In accordance with the permanent teeth, the size of the deciduous teeth also proved to be at the top of the range for populations of European origin.