Valborg Baste

Prevalence of obstructive lung disease in a general population: relation to occupational title and exposure to some airborne agents.

BACKGROUND: The importance of occupational exposure to airborne agents in the development of obstructive disease is uncertain. Studying the relation in a community population has the benefit of reducing the healthy worker effect seen in studies of working populations. METHODS: The prevalence of obstructive lung disease was examined in a Norwegian general population aged 18-73 in a two phased cross sectional survey. In the second phase a stratified sample (n = 1512) of those responding in the first phase was invited for clinical and spirometric examination (attendance rate 84%). Attenders were asked to state all jobs lasting greater than 6 months since leaving school and to say whether they had been exposed to any of seven specific agents and work processes potentially harmful to the lungs. RESULTS: The prevalence of asthma and chronic obstructive lung disease was 2.4% and 5.4%, respectively; spirometric airflow limitation (FEV1/FVC less than 0.7 and FEV1 less than 80% of predicted values) was observed in 4.5% of the population. All jobs were categorised into three groups according to the degree of potential airborne exposure. Having a job with a high degree of airborne exposure increased the sex, age, and smoking adjusted odds ratio for obstructive lung disease (asthma and chronic obstructive lung disease) by 3.6 (95% confidence interval 1.3 to 9.9) compared with having a job without airborne exposure; the association with spirometric airflow limitation was 1.4 (0.3 to 5.2). Occupational exposures to quartz, metal gases, aluminium production and processing, and welding were significantly associated with obstructive lung disease after adjusting for sex, age, and smoking habit, the adjusted odds ratios varying between 2.3 and 2.7. Occupational exposure to quartz and asbestos was significantly related to spirometric airflow limitation in people older than 50. CONCLUSION: Occupational title and exposure to specific agents and work processes may be independent markers of obstructive lung disease in the general population.

Maternal smoking and birthweight: effect modification of period, maternal age and paternal smoking

Objective. To study the effect on birthweight of maternal smoking, and its modification by study period, maternal age and paternal smoking.

Folate Supplementation and Twin Pregnancies

Background: Women in many countries are advised to increase their folate intake to lower the risk of neural tube defects. For this purpose several countries add folate to the flour. Therefore, it is important to monitor possible adverse effects of this B vitamin. We have assessed the effect of folate on twin pregnancies. Methods: We conducted a retrospective, population-register based study of 176,042 women who gave birth from December 1998 through the end of 2001. Use of folate and multivitamin supplements was recorded on the mandatory birth notification form of the Medical Birth Registry of Norway. Pregnancies after in vitro fertilization (IVF) were reported separately. Results: With adjustment for maternal age and parity, we observed an increased risk of twin pregnancies associated with preconceptional use of folate (odds ratio = 1.59; 95% confidence interval = 1.41–1.78). This association was largely explained by confounding with IVF pregnancies, which were strongly associated both with twin pregnancies and folate use. After exclusion of known IVF pregnancies, and accounting for underreporting of both IVF pregnancies and folate use, the risk was no longer elevated (1.02; 0.85–1.24). Weak associations with twin pregnancies were observed for use of multivitamins and folate during pregnancy, but could be due to increased use of vitamins after a recognized twin pregnancy. Conclusions: The association between preconceptional folate use and twin pregnancies was strongly confounded by IVF. After accounting for IVF pregnancies and underreporting, we found no evidence for an association between preconceptional folate supplements and twinning.

Obstetrical and neonatal outcome in pregnant patients with rheumatic disease

Possible associations between inflammatory rheumatic and connective tissue disease and adverse pregnancy outcome were assessed by using the Medical Birth Registry of Norway during the years 1967-95. All women with rheumatic disease were compared to women without such disease. Data on pregnancy outcome and deliveries were analyzed after adjustment for possible confounding factors. Women with rheumatic disease had significantly higher rates of preeclampsia, premature delivery and cesarean section as well a significantly increased relative risk of SGA children in all diagnostic groups in 1967-95. These findings emphasize the importance of close monitoring of pregnancy and delivery not only in patients with connective tissue disease, but also in patients with other inflammatory rheumatic disease.

Secular trends in breastfeeding and parental smoking

To explore the association between smoking and breastfeeding, we obtained data from a retrospective questionnaire‐based national survey comprising a random sample (n= 34 799) of all mothers giving birth in Norway 1970‐91. Variables studied were postpartum smoking habits for both parents, duration of breastfeeding, infants year of birth and parental age. The response rate was 70% (n= 24 438). During the study period, the maternal postpartum smoking prevalence decreased from 38% to 26%. The proportion breastfeeding at 6 months increased from 15% to 44% among smokers, and from 30% to 72% among non‐smokers. In spite of a considerable increase in breastfeeding both among smokers and non‐smokers, the proportion of breastfeeding, non‐smoking women at 6 months was twice that of smoking women during the whole period. Furthermore, the duration of breastfeeding was shorter among young mothers and when the fathers were smoking. There was epidemiological evidence that the effect on breastfeeding of smoking might represent both biological and social mechanisms.

Pregnancy complications and delivery practice in women with connective tissue disease and inflammatory rheumatic disease in Norway

Objective. To assess possible associations between inflammatory rheumatic disease and pregnancy complications/delivery practice.

Validity of a rheumatic disease diagnosis in the Medical Birth Registry of Norway

Background.  In our population‐based study of pregnancy outcome in women with rheumatic disease we based our assessment on the Medical Birth Registry of Norway (MBRN). We evaluated the MBRN as a source of data for such epidemiologic research by assessing the validity of a diagnosis of rheumatic disease in the MBRN against a gold standard. The validity may also be interpreted as a quality indicator, reflecting an obstetricians attention to rheumatic diseases in pregnancy.

Perinatal outcome in pregnancies of women with connective tissue disease and inflammatory rheumatic disease in Norway

Perinatal outcome in infants of women with rheumatic disease notified between 1967 95 to the Medical Birth Registry of Norway was compared to women without such disease. Logistic regression provided odds ratios for associations between rheumatic disease and perinatal outcome for 3 time periods: 1967-76, 1977-86, and 1987-95. Women with rheumatic disease had significantly higher rates of preterm birth than references and this was only partly correlated to the increased occurrence of preeclampsia. The risk of small for gestational age (SGA) infants was significantly higher both in women with connective tissue disease (CTD) and inflammatory arthritides. The proportion of infants with Apgar score < = 6 after 1 minute and 5 minutes was significantly increased in the CTD group indicating moderate to severe fetal asfyxia. The rate of perinatal mortality was high in the CTD group and postperinatal mortality was increased in infants born to mothers with rheumatic disease. Thus, rheumatic disease not only comprises pregnancy outcome, but increases the risk of adverse perinatal outcome.

Worse patient-reported outcome after lateral approach than after anterior and posterolateral approach in primary hip arthroplasty: A cross-sectional questionnaire study of 1,476 patients 1–3 years after surgery

Background — The surgical approach in total hip arthroplasty (THA) is often based on surgeon preference and local traditions. The anterior muscle-sparing approach has recently gained popularity in Europe. We tested the hypothesis that patient satisfaction, pain, function, and health-related quality of life (HRQoL) after THA is not related to the surgical approach. Patients — 1,476 patients identified through the Norwegian Arthroplasty Register were sent questionnaires 1–3 years after undergoing THA in the period from January 2008 to June 2010. Patient-reported outcome measures (PROMs) included the hip disability osteoarthritis outcome score (HOOS), the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), health-related quality of life (EQ-5D-3L), visual analog scales (VAS) addressing pain and satisfaction, and questions about complications. 1,273 patients completed the questionnaires and were included in the analysis. Results — Adjusted HOOS scores for pain, other symptoms, activities of daily living (ADL), sport/recreation, and quality of life were significantly worse (p < 0.001 to p = 0.03) for the lateral approach than for the anterior approach and the posterolateral approach (mean differences: 3.2–5.0). These results were related to more patient-reported limping with the lateral approach than with the anterior and posterolateral approaches (25% vs. 12% and 13%, respectively; p < 0.001). Interpretation — Patients operated with the lateral approach reported worse outcomes 1–3 years after THA surgery. Self-reported limping occurred twice as often in patients who underwent THA with a lateral approach than in those who underwent THA with an anterior or posterolateral approach. There were no significant differences in patient-reported outcomes after THA between those who underwent THA with a posterolateral approach and those who underwent THA with an anterior approach.

Infertility and spontaneous abortion among female hairdressers: the Hordaland Health Study.

Objectives:The authors investigated the risks of negative reproductive outcome among female hairdressers. Methods:A cross-sectional study was conducted in 1997–1999, and 16,907 women in their forties were invited (response 71%). Information on infertility, delayed conception, spontaneous abortions, smoking, education, and occupation was collected. Results:Infertility and spontaneous abortion were higher among female hairdressers than among women in other occupations (adjusted relative risks = 1.30; 95% confidence intervals = 1.08 to 1.55 and 1.31; 1.07 to 1.60, respectively). There was a significant interaction between work and smoking habits. Smoking increased the risk of infertility among women in other occupations, but this was not found among hairdressers. Conclusions:Female hairdressers have an increased risk of infertility and spontaneous abortions that might be due to their occupational chemical exposure. The risk was primarily found among never smokers.