Esa Läärä

Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study

BACKGROUND Dietary vitamin D supplementation is associated with reduced risk of type 1 diabetes in animals. Our aim was to ascertain whether or not vitamin D supplementation or deficiency in infancy could affect development of type 1 diabetes. METHODS A birth-cohort study was done, in which all pregnant women (n=12055) in Oulu and Lapland, northern Finland, who were due to give birth in 1966 were enrolled. Data was collected in the first year of life about frequency and dose of vitamin D supplementation and presence of suspected rickets. Our primary outcome measure was diagnosis of type 1 diabetes by end of December, 1997. FINDINGS 12058 of 12231 represented live births, and 10821 (91% of those alive) children were followed-up at age 1 year. Of the 10366 children included in analyses, 81 were diagnosed with diabetes during the study. Vitamin D supplementation was associated with a decreased frequency of type 1 diabetes when adjusted for neonatal, anthropometric, and social characteristics (rate ratio [RR] for regular vs no supplementation 0.12, 95% CI 0.03-0.51, and irregular vs no supplementation 0.16, 0.04-0.74. Children who regularly took the recommended dose of vitamin D (2000 IU daily) had a RR of 0.22 (0.05-0.89) compared with those who regularly received less than the recommended amount. Children suspected of having rickets during the first year of life had a RR of 3.0 (1.0-9.0) compared with those without such a suspicion. INTERPRETATION Dietary vitamin D supplementation is associated with reduced risk of type 1 diabetes. Ensuring adequate vitamin D supplementation for infants could help to reverse the increasing trend in the incidence of type 1 diabetes.

Risk Factors of Age-related Maculopathy in a Population 70 Years of Age or Older

PURPOSE To evaluate possible risk factors for age-related maculopathy (ARM) in an epidemiologic cross-sectional population study of inhabitants 70 years of age or older in a rural area in Oulu County, Northern Finland. METHODS Five hundred of the 560 (89 percent) eligible subjects were examined. The diagnosis of ARM was based on fundus photographs in 83 percent of the population or on ophthalmoscopic findings in 13 percent; in 4 percent, the fundi could not be seen. Both early and late forms of ARM were included. RESULTS The prevalence of ARM increased steadily with age without overall significant difference between men and women. The condition was, however, related to high body mass index in men. The ARM appeared to be also associated with the presence of cataract, broad peripapillary atrophy, and severe sclerosis of the retinal arteries, but after controlling for age, these associations were nonsignificant. No association was found between ARM and systemic hypertension, diabetes, smoking, working outside, myopia, glaucoma, or the presence of exfoliation. In logistic regression analysis, age was the only statistically significant risk factor for ARM in both sexes. In men, a high body mass index also was found to be a predictor for ARM. CONCLUSIONS The presence of ARM was associated with cataract and signs of age-related vascular changes in the eyes. Of the general factors, age in both sexes and high body mass index in men were found to be the only predictors of ARM.

Incremental effectiveness of pneumococcal vaccine on simultaneously administered influenza vaccine in preventing pneumonia and pneumococcal pneumonia among persons aged 65 years or older.

The effectiveness of simultaneously administered influenza and pneumococcal vaccines vs. influenza vaccine alone in preventing pneumonia, pneumococcal pneumonia and pneumococcal bacteraemia among the elderly was studied. The vaccines were offered to all persons aged 65 years or older (N=43,500) living in 35 administrative districts in Northern Finland. A total of 26,925 persons (62%) decided to participate. Allocation to the vaccination groups took place by year of birth (odd/even). The total follow-up of those vaccinated consisted of 38,037 person years. The incremental effectiveness of the pneumococcal vaccine was -20 (95% CI -50- + 10%) for pneumonia, -20 (95% CI -90- + 20%) for pneumococcal pneumonia and + 60% (95% CI -40- +90%) for pneumococcal bacteraemia. Thus the pneumococcal polysaccharide vaccine did not offer any additional protection from pneumonia among elderly people in Finland although it reduced the incidence of bacteraemia.

Serological evidence of an association between Chlamydia pneumoniae infection and lung cancer

Epidemiological evidence suggests that airway obstruction is an independent risk factor for lung cancer and that this cannot be explained by active or passive smoking alone. Chlamydia pneumoniae infection has been associated with chronic bronchitis and its exacerbates. Our aim was to evaluate the association between chronic C. pneumoniae infection and risk of lung cancer among male smokers. Smoking males with lung cancer (n = 230) and their age‐ and locality‐matched controls were selected among participants of the Alpha‐Tocopherol, Beta‐Carotene Cancer Prevention Study. The presence of C. pneumoniae infection was assessed by analyzing specific antibodies and immune complexes in 2 serum samples collected with a 3‐year interval before the lung cancer diagnosis. The diagnosis of chronic infection was based on stable levels of positive specific IgA antibody (titer ≥ 16) and immune complex (titer ≥ 4). Relative risks were estimated by odds ratios (OR) adjusted for age, locality and smoking history by a conditional logistic regression model. Markers suggesting chronic C. pneumoniae infection were present in 52% of cases and 45% of controls and hence were positively associated with the incidence of lung cancer (OR 1.6; 95% confidence interval [CI] 1.0–2.3). The incidence was especially increased in men younger than 60 years (OR 2.9; 95% CI 1.5–5.4) but not in the older age group (OR 0.9; 95% CI 0.5–1.6). Before concluding that C. pneumoniae infection is a new independent risk factor for lung cancer, corroboration from other studies with larger number of cases and longer follow‐up is needed. Int. J. Cancer 74:31–34.

Relationship between Field Strength and Abnormal Development in Chick Embryos Exposed to 50 Hz Magnetic Fields

Chick embryos were exposed to sinusoidally oscillating 50 Hz magnetic fields during their first 2 days of development. In the first series of experiments magnetic field strengths of 0.1, 0.3, 1 and 10 A/m were used. The percentage of abnormal embryos (% AE) was 16 per cent in the sham-exposed control group. % AE was increased at 1 A/m (29 per cent) and 10 A/m (32 per cent), but not at 0.1 A/m (16 per cent) or 0.3 A/m (14 per cent). In the second series of experiments field strengths of 0.4, 0.6, 0.9 and 1.35 A/m were used. % AE was 17 per cent in the control group, 10 per cent at 0.4 A/m, 19 per cent at 0.6 A/m, 17 per cent at 0.9 A/m and 36 per cent at 1.35 A/m. Only the 1.35 A/m group was significantly different from the controls. The results of this study suggest that exposure of chick embryos to a 50 Hz magnetic field causes abnormal development, and that no abnormalities are induced below a threshold between 0.9 and 1 A/m.

Comparison of ultrasound, radiography, and clinical examination in the diagnosis of acute maxillary sinusitis: a systematic review

The objective of this study was to assess the discriminative properties of the methods for diagnosing acute maxillary sinusitis (AMS) in unselected patients. The study design was a systematic review of evaluation studies identified by using Medline, by searching reference lists, by hand searches, and by contacting investigators. Evaluation studies were conducted anywhere in the world. Subjects were adults with suspected AMS. Main outcome measures were: sensitivity, specificity, positive and negative likelihood ratios of the primary studies, weighted means of these parameters in each comparison (clinical examination, radiography, and ultrasound compared to a reference standard in diagnosing AMS), and summary ROC curves and their Q* points where sensitivity equals specificity. For the years from 1962 to present, 49 study reports were found; 11 articles on studies that included a total of 1144 patients were eligible. Compared to sinus puncture, radiography was the most accurate method for diagnosing AMS: the Q* point on the summary ROC curve was 0.82 (95% confidence interval, CI, 0.78-0.85). Ultrasound was slightly less accurate than radiography compared to sinus puncture (Q* 0.80, 95% CI 0.76-0.83). Only two articles reported clinical examination compared to sinus puncture and the Q* for them was 0.75 (95% 0.58-0.86). Clinical examination is a rather unreliable method for diagnosing AMS, even in the hands of experienced specialists. Using radiography or ultrasound improves the accuracy of diagnosis. The diagnosis of AMS is rarely studied in primary care settings. Future comparative trials should preferably combine diagnosis and treatment, evaluating the two aspects of clinical management as unit.

Background Factors Predicting Non-Response in a Health Survey of Northern Finnish Young Men

The study addresses the characteristics potentially predictive of non-response to a health survey among 2500 24-year-old males, on whom a notable amount of other data was available. The overall non-response rate was 40%, part of which was due to the unreachability of some subjects: 4% of the questionnaires were returned because of unknown addresses. Some (n = 39) of the respondents had concealed the identification number in the questionnaire, which made it impossible to link these data to those collected before in their cases. We were therefore able to use effectively the data on 1450 (58%) responding subjects in this paper. Failure to respond was more common among the subjects who had lived in towns in their youth, had not grown up in a complete family, whose socioeconomic status of the family was unknown, and whose mother was young and had a low educational level. Poorer-than-average school performance at elementary school was also predictive of a high non-response rate. Non-response was heavily associated with previous non-response to a health inquiry. Some aspects of health and behaviour in adolescense, such as smoking at the age of 14, were related to non-response to this survey, too. The non-response was higher than average among those subjects who had suffered from mental disorders (serious mental disorders, less serious mental disorders such as neurotic disorders, adjustment reactions, and psychosomatic disorders and mental retardation). The young men who were employed, were students or were doing military service at the age 24 responded better than those who were unemployed or at disability pension.

Cow's milk consumption, disease-associated autoantibodies and Type 1 diabetes mellitus: A follow-up study in siblings of diabetic children

Evidence from case–control studies for the diabetogenicity of introduction of cow’s milk‐based formulas at early age in infancy is inconclusive. We followed siblings of children with Type 1 diabetes mellitus (Type 1 DM) to investigate a possible relationship between cow’s milk consumption during infancy or later in childhood and the emergence of diabetes‐associated autoantibodies and progression to clinical Type 1 DM. A cohort of 725 initially unaffected 0 to 25‐year‐old siblings of 801 index children with Type 1 DM diagnosed in 1986–1989 participated in the study (82 % of those invited). The siblings were observed for Type 1 DM associated autoantibodies at intervals of 3–12 months for 4 years, starting from the diagnosis of Type 1 DM in the index child. The follow‐up for Type 1 DM started at the same time and ended on 31 October 1995. The combined prevalence of Type 1 DM associated autoantibodies (islet cell antibodies (ICA), insulin autoantibodies (IAA), GAD autoantibodies (GADA), and/or antibodies to the insulinoma associated cDNA2 protein (IA‐2A)) was 13.6 % (95/697) at the beginning of the study. Of the initially seronegative siblings, 7.5 % (45/602) converted to antibody positivity during 4 years, and of all siblings 4.6 % (33/725) developed Type 1 DM during the total follow‐up time. The age at introduction of supplementary milk feeding was not significantly related to seroconversion to positivity for Type 1 DM associated autoantibodies or to the development of Type 1 DM in the siblings. When adjusted for age, sex, infant feeding patterns, and maternal age and education, high milk consumption in childhood (≥3 glasses daily) was associated with more frequent emergence of Type 1 DM‐associated autoantibodies than low consumption (<3 glasses daily) (adjusted odds ratio 3.97, 95 % confidence interval 1.3–11.7, p = 0.01). There was a non‐significant association between high milk consumption and progression to clinical Type 1 DM (adjusted hazard ratio 2.75, 95 % confidence interval 0.9–8.4, p = 0.07). To conclude, this study suggests that high consumption of cow’s milk during childhood may be associated both with seroconversion to positivity for diabetes‐associated autoantibodies and progression to clinical Type 1 DM among siblings of children with diabetes.

Self-reported health problems and sickness absence in different age groups predominantly engaged in physical work

Objectives: To study the associations between self-reported health problems and sickness absence from work. Methods: The results of a questionnaire survey were combined with archival data of sickness absence of 1341 employees 88 males; 62 blue-collar in the construction, service and maintenance work within one corporation in Finland. Sex, age and occupational grading were controlled as confounders. A zero-inflated negative binomial ZINB regression model was used in the statistical analysis of sickness absence data. Results: The prevalence of self-reported health problems increased with age, from 23 in 1830-year-olds to 54 in 5561-year-olds. However, in those aged 1830 years, 71 had been absent from work and in those aged 5561 years this proportion was 53. When health problems and occupational grading were accounted for in the ZINB model, age as such was not associated with the number of days on sick leave, but the young workers still had higher propensity for any sickness absence than the old. Self-rated future working ability and musculoskeletal impairment were strong determinants of sickness absence. Among those susceptible to taking sick leave, the estimated mean number of absence days increased by 14 for each rise of 1 unit of the impairment score scale 010. Conclusions: Young subjects had surprisingly high probability for sickness absence although they reported better health than their older colleagues. A higher total count of absence days was found among subjects reporting health problems and poorer working ability, regardless of age, sex and occupational grade. These findings have implications for both management and the healthcare system in the prevention of work disability.

Systemic therapy with estrogen or estrogen with progestin has no effect on skin collagen in postmenopausal women

OBJECTIVES To investigate the effect of estrogen alone or combined with progestin on the amount and synthesis of skin collagen in postmenopausal women. METHODS Forty-three early postmenopausal women were enrolled into this open, non-randomized parallel-groups study. Fifteen women received a continuous oral dose of 2 mg of 17 beta-estradiol and 1 mg of norethisterone acetate daily and 14 women an oral dose of 2 mg estradiol valerate daily. Fourteen subjects served as controls. The histology and type I and III procollagen immunohistochemistry of the skin, skin thickness, the amount of total collagen determined by a colorimetric method and the synthesis of type I and III collagens determined by analysing procollagen propeptides in the suction blister fluid were studied before the treatment and at 6 and 12 months. The proportional area of elastic fibers and the thickness of the epidermis were assessed from the sections obtained before the treatment and at 12 months, with computerized image analysis. RESULTS Skin thickness, the amount and rate of collagen synthesis, the proportional area of elastic fibers and the thickness of the epidermis were not affected by either 17 beta-estradiol and 1 mg of norethisterone acetate or 2 mg of estradiol valerate. No histological or immunohistological changes were detected in the skin specimens during the 12-month treatment period compared to the baseline or to the skin specimens of the control group. CONCLUSIONS A 1-year treatment with systemic estrogen alone or combined with progestin does not change the amount of collagen or the rate of collagen synthesis in postmenopausal women.