EBNA-1 reactivity and HLA DRB1*1501 as statistically independent risk factors for multiple sclerosis: a case-control study

OBJECTIVES AND METHODS

The interaction between the two best documented risk factors (human leukocyte antigen [HLA] class II [DRB1*1501 positivity] and Epstein-Barr virus [elevated Epstein-Barr nuclear antigen 1 (EBNA-1) antibody reactivity]) for multiple sclerosis (MS) was studied in a case-control study of biobank samples from 109 MS cases and 212 matched referents.

RESULTS

Multivariate logistic regression analysis showed that both were statistically significant in both sexes. HLA DRB1*1501-positive referents had higher EBNA-1 reactivity than HLA-negative referents. Less EBNA-1 reactivity was required to increase the MS risk in HLA DRB1*1501-positives than in HLA-negatives.

CONCLUSION

We suggest that HLA DRB1*1501-positive individuals have an increased vulnerability to EBV-induced autoimmunity.

Gender differences and temporal variation in the incidence of type 1 diabetes: results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002

OBJECTIVES

To establish the gender difference amongst newly diagnosed type 1 diabetic patients aged 15-34 years, considering age at diagnosis, temporal trend and seasonal variation at time of diagnosis.

STUDY DESIGN

A population-based prospective study with a mean annual population at risk of 2.3 million.

SETTING

All departments of medicine, endocrinology and paediatrics and primary health care units in Sweden.

SUBJECTS

Incident cases of diabetes aged 15-34 years at diagnosis 1983-2002. MEASURE INSTRUMENT: Basic characteristics of patients at diagnosis were reported by the diagnosing doctor on a standardized form. Level of ascertainment was estimated at 80-90%.

RESULTS

Amongst all incident cases (n = 8012), 74% was diagnosed with type 1 diabetes. The mean annual incidence rate of type 1 diabetes was 12.7/100,000, in men 16.4/100,000 and in women 8.9/100,000. The incidence of type 1 diabetes decreased slowly by increasing age but was in all age groups higher in men, yielding an overall male/female ratio of 1.8. In both genders the incidence of type 1 diabetes decreased in average of 1.0% per year. A seasonal pattern with significantly higher incidence during January-March and lower during May-July was seen in both genders.

CONCLUSIONS

A clear male predominance of type 1 diabetes was seen in all ages. The temporal trend and the seasonal pattern was similar in men and women. Hence, internal factors related to the gender rather than differences in the exposure to environmental factors seem to explain the consistent male-female bias in the postpubertal risk of developing type 1 diabetes.

Comparison of active and passive case detection systems in Jepara District, Indonesia

This study compares the role and performance of active case detection (ACD) and passive case detection (PCD) in Jepara district, Indonesia. The number of blood slides examined and positive for malaria reported from 1994-1998 was retrieved from the district surveillance registers. Age of cases, parasite species, types of drugs and dosage, and time lapse were recorded from malaria registers at the three most endemic health centres. The quality of diagnosis was examined by re-reading 153 slides at the Department of Parasitology, Faculty of Medicine, Gadjah Mada University. Almost 60% of the 10,493 confirmed cases in Jepara district were identified from ACD. ACD detected significantly higher P. falciparum gametocyte infections than PCD (14.7% vs. 5.7%; p=0.002). The duration for slides prepared for examination was longer in ACD than in PCD (2.3 vs. 1.1 days; p<0.001), but this was still within the presumptive treatment period. Based on this we conclude that in the transition period to a decentralised health system, ACD for malaria parasites should be continued in a specified endemic area and therefore, efforts to retain the village malaria workers should be considered.

Randomised controlled trial of two antenatal care models in rural Zimbabwe

OBJECTIVE

To compare a five-visit antenatal care (ANC) model with specified goals with the standard model in a rural area in Zimbabwe.

DESIGN

Cluster randomised controlled trial with the clinic as the randomisation unit.

SETTING

Primary care setting in a developing country where care was provided by nurse-midwives.

POPULATION

Women booking for ANC in the clinics were eligible.

MAIN OUTCOME MEASURES

Number of antenatal visits, antepartum and intrapartum referrals, utilization of health centre for delivery and perinatal outcomes.

METHODS

Twenty-three rural health centres were stratified prior to random allocation to the new (n = 11) or standard (n = 12) model of care.

RESULTS

We recruited 13,517 women (new, n = 6897 and standard, n = 6620) in the study, and 78% (10,572) of their pregnancy records were retrieved. There was no difference in median maternal age, parity and gestational age at booking between women in the standard model and those in the new model. The median number of visits was four for both models. The proportion of women with five or less visits was 77% in the new and 69% in the standard model (OR 1.5; 95% CI 1.08-2.2). The likelihood of haemoglobin testing was higher in the new model (OR 2.4; 95% CI 1.0-5.7) but unchanged for syphilis testing. There were fewer intrapartum transfers (5.4 versus 7.9% [OR 0.66; 95% CI 0.44-0.98]) in the new model but no difference in antepartum or postpartum transfers. There was no difference in rates of preterm delivery or low birthweight. The perinatal mortality was 25/1000 in standard model and 28/1000 in new model.

CONCLUSION

In Gutu district, a focused five-visit schedule did not change the number of contacts but was more effective as expressed by increased adherence to procedures and better use of institutional health care.

Lower levels of plasma 25-hydroxyvitamin D among young adults at diagnosis of autoimmune type 1 diabetes compared with control subjects: results from the nationwide Diabetes Incidence Study in Sweden (DISS)

AIMS/HYPOTHESIS

Low plasma vitamin D concentrations may promote the development of type 1 diabetes. To test this hypothesis, we measured plasma 25-hydroxyvitamin D (25OHD) in young adults with type 1 diabetes.

METHODS

The nationwide Diabetes Incidence Study in Sweden (DISS) covers 15- to 34-year-old people with newly diagnosed diabetes. Blood samples at diagnosis were collected during the 2-year period 1987/1988. Patients with islet antibodies (islet cell antibodies, GAD antibodies or tyrosine phosphatase-like protein antibodies) were defined as having autoimmune type 1 diabetes. Plasma 25OHD was measured in samples taken from 459 patients at the time of diagnosis, and in 138 of these subjects 8 years later. The results were compared with age- and sex-matched control subjects (n=208).

RESULTS

At diagnosis, plasma 25OHD levels were significantly lower in patients with type 1 diabetes than in control subjects (82.5+/-1.3 vs 96.7+/-2.0 nmol/l; p<0.0001). Eight years later, plasma 25OHD had decreased in patients (81.5+/-2.6 nmol/l; p=0.04). Plasma 25OHD levels were significantly lower in diabetic men than in diabetic women at diagnosis (77.9+/-1.4 vs 90.1+/-2.4 nmol/l; p<0.0001) and at follow-up (77.1+/-2.8 nmol/l vs 87.2+/-4.5 nmol/l; p=0.048).

CONCLUSIONS/INTERPRETATION

The plasma 25OHD level was lower at diagnosis of autoimmune type 1 diabetes than in control subjects, and may have a role in the development of type 1 diabetes. Plasma 25OHD levels were lower in men than in women with type 1 diabetes. This difference may be relevant to the high incidence of type 1 diabetes among young adult men.

HLA-DQB1 genotypes, islet antibodies and beta cell function in the classification of recent-onset diabetes among young adults in the nationwide Diabetes Incidence Study in Sweden

AIMS/HYPOTHESIS

The World Health Organization considers an aetiological classification of diabetes to be essential. The aim of this study was to evaluate whether HLA-DQB1 genotypes facilitate the classification of diabetes as compared with assessment of islet antibodies by investigating young adult diabetic patients.

SUBJECTS AND METHODS

Blood samples were available at diagnosis for 1,872 (90%) of the 2,077 young adult patients (aged 15-34 years old) over a 5-year period in the nationwide Diabetes Incidence Study in Sweden. Islet antibodies were measured at diagnosis in 1,869 patients, fasting plasma C-peptide (fpC-peptide) after diagnosis in 1,522, while HLA-DQB1 genotypes were determined in 1,743.

RESULTS

Islet antibodies were found in 83% of patients clinically considered to have type 1 diabetes, 23% with type 2 diabetes and 45% with unclassifiable diabetes. After diagnosis, median fpC-peptide concentrations were markedly lower in patients with islet antibodies than in those without (0.24 vs 0.69 nmol/l, p<0.0001). Irrespective of clinical classification, patients with islet antibodies showed increased frequencies of at least one of the risk-associated HLA-DQB1 genotypes compared with patients without. Antibody-negative patients with risk-associated HLA-DQB1 genotypes had significantly lower median fpC-peptide concentrations than those without risk-associated genotypes (0.51 vs 0.74 nmol/l, p=0.0003).

CONCLUSIONS/INTERPRETATION

Assessment of islet antibodies is necessary for the aetiological classification of diabetic patients. HLA-DQB1 genotyping does not improve the classification in patients with islet antibodies. However, in patients without islet antibodies, HLA-DQB1 genotyping together with C-peptide measurement may be of value in differentiating between idiopathic type 1 diabetes and type 2 diabetes.

Survival from invasive breast cancer among interval cases in the mammography screening programmes of northern Sweden

The aim of this study was to estimate breast cancer survival according to detection mode for 5120 women with invasive breast cancer, in particular for those detected in the screening intervals. We found a significant survival difference in favour of women with cancer detected in the screening intervals (n=729) compared with those uninvited (n=1879) during the 13-year follow-up. Detection mode was proven to modify the prognostic effect of stage. Women with stage I interval cancer had shorter survival and those with stage II had longer survival than expected. It is suggested that interval cancers might consist of two subgroups with different behaviour: one of fast-growing tumours presenting as stage I cases and another of slow-growing tumours presenting as stage II+ cases. A hypothesis related to this observation is discussed.

Excess mortality in incident cases of diabetes mellitus aged 15 to 34 years at diagnosis: a population-based study (DISS) in Sweden

AIMS/HYPOTHESIS

The objective of the study was to analyse the mortality, survival and cause of death patterns in incident cases of diabetes in the 15-34-year age group that were reported to the nationwide prospective Diabetes Incidence Study in Sweden (DISS).

MATERIALS AND METHODS

During the study period 1983-1999, 6,771 incident cases were reported. Identification of deaths was made by linking the records to the nationwide Cause of Death Register.

RESULTS

With an average follow-up of 8.5 years, resulting in 59,231 person-years, 159 deaths were identified. Diabetes was reported as the underlying cause of death in 51 patients (32%), and as a contributing cause of death in another 42 patients (26%). The standardised mortality ratio (SMR) was significantly elevated (RR=2.4; 95% CI: 2.0-2.8). The SMR was higher for patients classified by the reporting physician as having type 2 diabetes at diagnosis than for those classified as type 1 diabetic (2.9 and 1.8, respectively). Survival analysis showed significant differences in survival curves between males and females (p=0.0003) as well as between cases with different types of diabetes (p=0.005). This pattern was also reflected in the Cox regression model showing significantly increased hazard for males vs females (p=0.0002), and for type 2 vs type 1 (p=0.015) when controlling for age.

CONCLUSIONS/INTERPRETATION

This study shows a two-fold excess mortality in patients with type 1 diabetes and a three-fold excess mortality in patients with type 2 diabetes. Thus, despite advances in treatment, diabetes still carries an increased mortality in young adults, even in a country with a good economic and educational patient status and easy access to health care.

Vehicle exhaust exposure in an incident case-control study of adult asthma

The objective of this case-control study was to evaluate whether traffic-related air pollution exposure at home increases the risk of asthma in adults and to compare two commonly used exposure variables and differences between urban and rural living. Incident cases of asthma and matched controls of subjects aged 20-60 yrs were recruited in Luleå, Sweden. In total 203 cases and 203 controls were enrolled in the study. Exposure was estimated by traffic flow and measured levels of outdoor nitrogen dioxide (NO2) in the surrounding environment of each home, respectively. The relationship between measured levels of NO2 and traffic flow was studied using linear regression. The results indicated a nonsignificant tendency between living in a home close to a high traffic flow and an increased risk of asthma. The association between asthma and measured NO2 was weak and not significant, but the skin-prick test result acted as an effect modifier with a borderline significant association among positives. The correlation between traffic flow and outdoor NO2 was low. The results suggest that living close to high traffic flows might increase the asthma incidence in adults, while the tendency for nitrogen dioxide was only seen among atopics. Traffic flow and nitrogen dioxide had a lower than expected correlation.

Effectiveness of referral system for antenatal and intra-partum problems in Gutu district, Zimbabwe

We conducted a population-based cohort study to determine the prevalence of antenatal and intra-partum referrals, compliance with advice and perinatal outcomes in referred pregnant women in Gutu district, Zimbabwe. The cohort was composed of 10,572 women who received antenatal care in 23 rural health centres (RHC) in Gutu district between January 1995 and June 1998. Pregnancy records of women with antenatal or intra-partum referral were analysed for indication, compliance and perinatal outcomes. Using women who had no antenatal referral or those who complied as referents, the association of referral with perinatal outcome was expressed as relative risk (RR) with 95% confidence intervals (CI). A total of 30% of women (3,094/10,572) had an antenatal referral. Among women attending RHC in labour, 13% (694/5,338) were referred intra-partum. Nulliparous and women younger than 20 years were more likely to be referred. Nurse - midwives' compliance with referral recommendations was low as 59% women with historical risk factors and 52% with raised blood pressure (>140/90 mmHg) were not referred. Women complied with referral advice except when indication was high parity. Women with antenatal referral were more likely to have hospital delivery, 70% vs 18% (p < 0.001). A total of 13% (993/7,478) of women referred themselves for hospital delivery. The risk of perinatal death was elevated among intra-partum referrals (RR 3.4; 95% CI 1.7 - 6.8), self-referrals (RR 2.6; 95% CI 1.5 - 4.5) and also among women with historical risk factors who were not referred (RR 4.8; 95% CI 2.5 - 9.2). We concluded that although there was a functional referral system in Gutu district its efficiency was reduced by failure of health personnel to comply with referral recommendations. Women took appropriate action for most referral indications.

Increased risk of diabetes among relatives of female insulin-treated patients diagnosed at 15-34 years of age

AIMS

This study aimed to determine the risk of developing diabetes among relatives of patients diagnosed between 15 and 34 years of age who were treated with insulin. Our second aim was to determine whether there was a difference in risk of diabetes between relatives of male and female patients.

METHODS

A questionnaire was sent to patients in the Diabetes Incidence Study in Sweden registry diagnosed between 1983 and 1993 to determine the presence of first-degree relatives with diabetes.

RESULTS

In 3087 index patients treated with insulin, 17.8% (95% confidence interval 16.5, 19.2) had a first-degree relative (excluding offspring) treated with insulin, the frequency being higher in female (19.8%) than in male (16.5%, P = 0.018) patients. A total of 10.7% had a parent treated with insulin. The prevalence of insulin-treated diabetes was higher among parents of female (12.5%) than of male (9.5%), insulin-treated index patients (P = 0.0068). A similar difference was observed using life table analysis (P = 0.0025), which also showed that the risk by 63 years of age was 7.6% for parents of female and 4.9% for parents of male insulin-treated index patients. In insulin-treated index patients, 8.4% had a sibling with insulin-treated diabetes.

CONCLUSIONS

We conclude that the risk for relatives of women with insulin-treated diabetes was higher than for relatives of insulin-treated male patients. We suggest that greater genetic susceptibility is required for females compared with males in the 15-34 age group in order to develop diabetes and hence females might carry more diabetes genes since more of their relatives also develop diabetes.

Hormone replacement therapy, body mass index and asthma in perimenopausal women: a cross sectional survey

BACKGROUND

Hormone replacement therapy (HRT) and obesity both appear to increase the risk of asthma. A study was undertaken to investigate the association of HRT with asthma and hay fever in a population of perimenopausal women, focusing on a possible interaction with body mass index (BMI).

METHODS

A postal questionnaire was sent to population based samples in Denmark, Estonia, Iceland, Norway, and Sweden in 1999-2001, and 8588 women aged 25-54 years responded (77%). Pregnant women, women using oral contraceptives, and women <46 years were excluded. Analyses included 2206 women aged 46-54 years of which 884 were menopausal and 540 used HRT. Stratified analyses by BMI in tertiles were performed.

RESULTS

HRT was associated with an increased risk for asthma (OR 1.57 (95% CI 1.07 to 2.30)), wheeze (OR 1.60 (95% CI 1.22 to 2.10)), and hay fever (OR 1.48 (95% CI 1.15 to 1.90)). The associations with asthma and wheeze were significantly stronger among women with BMI in the lower tertile (asthma OR 2.41 (95% CI 1.21 to 4.77); wheeze OR 2.04 (95% CI 1.23 to 3.36)) than in heavier women (asthma: p(interaction) = 0.030; wheeze: p(interaction) = 0.042). Increasing BMI was associated with more asthma (OR 1.08 (95% CI 1.05 to 1.12) per kg/m2). This effect was only found in women not taking HRT (OR 1.10 (95% CI 1.05 to 1.14) per kg/m2); no such association was detected in HRT users (OR 1.00 (95% CI 0.92 to 1.08) per kg/m2) (p(interaction) = 0.046). Menopause was not significantly associated with asthma, wheeze, or hay fever.

CONCLUSIONS

In perimenopausal women there is an interaction between HRT and BMI in the effects on asthma. Lean women who were HRT users had as high a risk for asthma as overweight women not taking HRT. It is suggested that HRT and overweight increase the risk of asthma through partly common pathways.

Association of asthma and hay fever with irregular menstruation

BACKGROUND

There is some evidence that asthmatic women are more likely to have abnormal sex hormone levels. A study was undertaken to determine whether asthma and allergy were associated with irregular menstruation in a general population, and the potential role of asthma medication for this association.

METHODS

A total of 8588 women (response rate 77%) participated in an 8 year follow up postal questionnaire study of participants of the ECRHS stage I in Denmark, Estonia, Iceland, Norway, and Sweden. Only non-pregnant women not taking exogenous sex hormones were included in the analyses (n = 6137).

RESULTS

Irregular menstruation was associated with asthma (OR 1.54 (95% CI 1.11 to 2.13)), asthma symptoms (OR 1.47 (95% CI 1.16 to 1.86)), hay fever (OR 1.29 (95% CI 1.05 to 1.57)), and asthma preceded by hay fever (OR 1.95 (95% CI 1.30 to 2.96)) among women aged 26-42 years. This was also observed in women not taking asthma medication (asthma symptoms: OR 1.44 (95% CI 1.09 to 1.91); hay fever: OR 1.27 (95% CI 1.03 to 1.58); wheeze preceded by hay fever: OR 1.76 (95% CI 1.18 to 2.64)). Irregular menstruation was associated with new onset asthma in younger women (OR 1.58 (95% CI 1.03 to 2.42)) but not in women aged 42-54 years (OR 0.62 (95% CI 0.32 to 1.18)). The results were consistent across centres.

CONCLUSIONS

Younger women with asthma and allergy were more likely to have irregular menstruation. This could not be attributed to current use of asthma medication. The association could possibly be explained by common underlying metabolic or developmental factors. The authors hypothesise that insulin resistance may play a role in asthma and allergy.

Birthweight and risk of type 1 diabetes in children and young adults: a population-based register study

AIMS/HYPOTHESIS

We investigated the association between type 1 diabetes and birthweight by age at disease onset.

METHODS

This population-based case-referent study used data from two nationwide case registers that are linked to the Swedish Medical Birth Registry and cover incident cases of type 1 diabetes in the 0- to 14-year (since 1 July 1977) and 15- to 34-year age groups (since 1 January 1983). Of the cases linked to the Medical Birth Registry, a total of 9,283 cases with onset before 15 years of age was recorded before 1 January 2003, and 1,610 cases were recorded with onset before 30 years of age and born after 1973 (together 95% of eligible cases). Multiple births and babies of diabetic mothers were excluded. Sex-specific birthweight by gestational week is expressed as multiples of the standard deviation (SDS) and adjusted for year of birth, maternal age and parity.

RESULTS

Cases with onset before 10 years of age (n = 5,792) showed a significant linear trend in odds ratio (OR) by SDS of adjusted birthweight (OR by SDS: 0.062; 95% CI: 0.037-0.086; p < 0.0001), while cases with onset at the age of 10-29 years showed no significant trend (OR by SDS: 0.004; 95% CI: -0.007 to 0.0014; p = 0.22).

CONCLUSIONS/INTERPRETATION

The association between type 1 diabetes risk and birthweight seems to be limited to cases with disease onset in younger years.

Comparison of early performance indicators for screening projects within the European Breast Cancer Network: 1989–2000

In 1989 the European Breast Cancer Network (EBCN) was established by the first pilot projects for breast cancer screening, co-funded by the Europe Against Cancer programme. We report early performance indicators for these EBCN projects while taking into account their organizational setting. Out of 17 projects in the network, 10 projects from six European countries contributed aggregated data on number of invitations, screening examinations, and breast cancers detected over the period 1989-2000. Results were summarized separately for projects in centralized versus decentralized health care environments. The European Guidelines for quality assurance in mammography screening provided reference values for the performance indicators. The most prominent finding in this study was the higher participation rate in centralized versus decentralized projects (average participation in 1998: 74 versus 33%; P<0.001), whereas the invitation system and screening policy in these projects were similar. Detection rates and characteristics of cancers detected at initial and subsequent screening examinations showed no significant differences between centralized and decentralized projects. Even though early performance indicators for centralized versus decentralized projects were similar, the impact of breast screening on mortality from this disease at the population level will differ since the decentralized projects reach only part of the target population.

A prospective study of asthma incidence and its predictors: the RHINE study

The objective of this longitudinal study was to estimate the incidence rate of asthma, and to compare the incidence between subjects with or without baseline reporting of certain respiratory symptoms. A follow-up of the random population samples in the European Respiratory Health Survey (ECRHS) in Sweden, Norway, Denmark, Iceland and Estonia was conducted in 1999-2001, in a population aged 30-54 yrs at follow-up (n=14,731). Asthma was defined as reporting either asthma or physician-diagnosed asthma, and a reported year when asthma symptoms were first noticed. Incidence rates, incidence rate ratios and hazard ratios were calculated with 95% confidence intervals. The incidence rate of asthma was 2.2 cases per 1,000 person-yrs. The incidence was higher among females (2.9 cases.1,000 person-yrs(-1)) than among males (1.5 cases.1,000 person-yrs(-1)). When subjects with baseline reporting of wheezing were excluded, the incidence rate decreased to 1.7 cases.1,000 person-yrs(-1), with a further decrease to 1.5 cases.1,000 person-yrs(-1) after exclusion of subjects with wheezing, nocturnal dyspnoea, chest tightness and cough. There was a strong association between onset of asthma and wheezing at baseline. In this prospective, population-based study, the incidence rate of asthma in the whole population sample ranged 1.5-2.2.1,000 person-yrs(-1), with a higher incidence range among females. The incidence was dependent on the extent to which subjects with respiratory symptoms were excluded from follow-up. Hence, for comparability between studies, the exclusion criteria in the follow-up population must be stated.

Obesity increases the risk of incident asthma among adults

The annual incidence of asthma in adults in northern Sweden has been estimated at 2.3 per thousand population. Risk factors for incident asthma among adults were studied in a case-referent study based on incident cases of asthma during 1995-1999. The healthcare providers reported suspected cases of incident asthma. After clinical examination, 309 (65% female) of 473 reported subjects were included. Inclusion criteria were a history of incident asthma (onset <12 months) and verified bronchial variability. Referents were randomly selected and stratified by age, sex and area of residence. The significant risk factors were hay fever, a family history of asthma, ex-smoking status and elevated body mass index (25.0-29.9 and > or =30). The risk factor pattern was similar for females and males, and increased body mass index was a significant risk factor for both males and females, as well as for allergic and nonallergic subjects. In conclusion, in addition to hay fever, a family history of asthma, allergic sensitisation and ex-smoking status, increased body mass index was a significant risk factor for incident asthma independent of sex and allergic status.

Insomnia is more common among subjects living in damp buildings

BACKGROUND

Insomnia is a condition with a high prevalence and a great impact on quality of life. Little is known about the relation between and sleep disturbances and the home environment.

AIM

To analyse the association between insomnia and building dampness.

METHODS

In a cross-sectional, multicentre, population study, 16 190 subjects (mean age 40 years, 53% women) were studied from Reykjavik in Iceland, Bergen in Norway, Umeå, Uppsala, and Göteborg in Sweden, Aarhus in Denmark, and Tartu in Estonia. Symptoms related to insomnia were assessed by questionnaire.

RESULTS

Subjects living in houses with reported signs of building dampness (n = 2873) had a higher prevalence of insomnia (29.4 v 23.6%; crude odds ratio 1.35, 95% CI 1.23 to 1.48). The association between insomnia and different indicators of building dampness was strongest for floor dampness: "bubbles or discoloration on plastic floor covering or discoloration of parquet floor" (crude odds ratio 1.96, 95% CI 1.66 to 2.32). The associations remained significant after adjusting for possible confounders such as sex, age, smoking history, housing, body mass index, and respiratory diseases. There was no significant difference between the centres in the association between insomnia and building dampness.

CONCLUSION

Insomnia is more common in subjects living in damp buildings. This indicates that avoiding dampness in building constructions and improving ventilation in homes may possibly have a positive effect on the quality of sleep.

Relation of parity to pregnancy outcome in a rural community in Zimbabwe

This population-based cohort study was conducted to compare pregnancy complications and outcome among nulliparous, low (1-5) and high (> or = 6) parity women. Women who registered for antenatal care and gave birth in Guru District, Zimbabwe, between January 1995 and June 1998 were classified into groups by parity. The women were compared for baseline characteristics, utilisation of health facilities and occurrence of pregnancy complications such as hypertensive disorders of pregnancy, haemorrhage, pre-term delivery, operative delivery, low birth weight and perinatal death. In estimating risk, primiparous (parity = 1) women were used as referents. Pregnancy records for 10,569 women were analysed. Mean ages of nulliparous and high parity (> or = 6) women were 20.1 and 37.7 years respectively (p < 0.001). Prevalence of anaemia at booking (haemoglobin < or =10.5 g/dl) was reduced in nulliparous compared to multiparous women (11.7% vs 16.8%; p > or = 0.001). Nulliparous women were likely to book early (< or = 20 weeks) for antenatal care, have a higher number of visits (> or = 6) and fewer home births. Nulliparous women had higher risk for low birth weight (RR 1.70; 95% CI 1.36 - 2.13). Compared to low parity women, nulliparous and high parity women had an elevated risk of hypertensive complications RR 1.62 (95% CI 1.37-1.92) and RR 1.64 (95% CI 1.29 - 2.07) respectively. The risk of developing any pregnancy complications was highest in nulliparous women (RR 1.48; 95% 1.31- 1.67). In conclusion, nulliparous women had an increased risk of pregnancy complications. High parity women with no previous complicated pregnancy were at low risk of complications.

An altered immune response to Epstein-Barr virus in multiple sclerosis: a prospective study

OBJECTIVE

To investigate the association between human herpesviruses and multiple sclerosis (MS), as well as between measles virus and MS.

METHODS

The authors identified prospectively collected serum samples from 73 MS cases and retrospective sera from 161 MS cases in two population-based serum bank registers. Analyses of IgG antibody responses in cases and matched referents were performed for Epstein-Barr virus (EBV [EBNA-1 and VCA]), human herpesvirus 6 (HHV-6), herpes simplex virus (HSV), varicella zoster virus (VZV), and measles.

RESULTS

All cases showed signs of past EBV infection. High activity to EBNA-1 and HHV-6 significantly (borderline significance for HHV-6) increased the risk for MS in prospective sera. A discrepancy between activities to EBNA-1 and VCA was striking in MS samples collected less than 5 years before relapsing-remitting MS onset, where high activity to EBNA-1 significantly increased, and high VCA activity significantly decreased the risk for MS. There was no support for major causal roles for HSV, VZV, or measles.

CONCLUSION

Individuals who will develop MS exhibit an altered immune response against the EBV virus characterized by a high IgG activity to EBNA-1 in the absence of high activity to VCA, this being most pronounced in the 5-year period preceding MS onset.

Early breast cancer deaths in women aged 40–74 years diagnosed during the first 5 years of organised mammography service screening in north Sweden

The aim of this study was to analyse individual cases of lethal breast cancer and not to evaluate the screening programme. Women aged 40-74 years who were diagnosed with breast cancer in 1990-94 and died on or before 31 December 1998, during the gradual introduction of organised mammography service screening in north Sweden, were included in the study. Out of 342 breast cancer deaths, 280 (82%) were in symptomatic patients whose cancers were clinically detected. Most breast cancers that proved fatal were already in an advanced stage and/or of high histological grade at the time of detection. A shift towards a lower stage was seen among screen-detected and interval-detected fatal cases. In a few of the cases with fatal outcome, in patients primarily presenting with histological grade I tumours of various sizes or small screen-detected tumours less than 10mm in size, early diagnosis by mammography followed by state-of-the-art treatment did not seem to have been enough to prevent death.

Normal weight promotes remission and low number of islet antibodies prolong the duration of remission in Type 1 diabetes

AIM

To identify clinical, immunological and biochemical factors that predict remission, and its duration in a large cohort of young adults with Type 1 diabetes mellitus (DM).

METHODS

In Sweden, 362 patients (15-34 years), classified as Type 1 DM were included in a prospective, nation-wide population-based study. All patients were followed at local hospitals for examination of HbA(1c) and insulin dosage over a median period after diagnosis of 5 years. Duration of remission, defined as an insulin maintenance dose </= 0.3 U/kg/24 h and HbA(1c) within the normal range, was analysed in relation to characteristics at diagnosis.

RESULTS

Remissions were seen in 43% of the patients with a median duration of 8 months (range 1-73). Sixteen per cent had a remission with a duration > 12 months. Among patients with antibodies (ab(+)), bivariate analysis suggested that adult age, absence of low BMI, high plasma C-peptide concentrations, lack of ketonuria or ketoacidosis at diagnosis and low insulin dose at discharge from hospital were associated with a high possibility of achieving remission. Multiple regression showed that normal weight (BMI of 20-24.9 kg/m(2)) was the only factor that remained significant for the possibility of entering remission. In survival analysis among ab(+) remitters, a low number of islet antibodies, one or two instead of three or four, were associated with a long duration of remissions.

CONCLUSION

In islet antibody-positive Type 1 DM, normal body weight was the strongest factor for entering remission, whilst a low number of islet antibodies was of importance for the duration.