Biomedical subjects

L Bodin

Publications and source records attributed to L Bodin.

At least 37 records · Page 2Linked to original sources

PubMed2001

Long-term, non-specific spinal pain: reliable and valid subgroups of patients.

The aim of this study was to identify reliable and valid subgroups of spinal pain patients, using data from the Swedish version of the Multidimensional Pain Inventory (MPI-S). A second aim was to test the generalisability of the three patient profiles described in earlier studies on the MPI ("adaptive coper", "dysfunctional" and "interpersonally distressed" patients). The study base consisted of two samples of individuals suffering from long-term, non-specific spinal pain and the results were validated across these samples. Cluster analysis was used to detect distinct groups of patients and the validity of these subgroups was evaluated on variables not used to generate the cluster solution. One subgroup was characterised by lower pain severity, lower interference with everyday activities, lower affective distress and higher life control than the other two subgroups. This patient profile was similar to the MPI adaptive coper patients. A second subgroup resembled the dysfunctional patient profile, thus displaying a worse adjustment to chronic pain than the AC patients. The third patient group reported significantly lower levels of social support from "significant others" than the other subgroups. This patient profile was similar to that of the interpersonally distressed patient group. Taken together, the results support the reliability, validity and generalisability of three subgroups of chronic pain patients derived from the MPI-S.

Adaptation, Psychological↗

PubMed2001

A randomized controlled component analysis of a behavioral medicine rehabilitation program for chronic spinal pain: are the effects dependent on gender?

The aim of the present study was to evaluate the outcome of a behavioral medicine (BM) rehabilitation program and the outcome of its two main components, compared to a 'treatment-as-usual' control group (CG). The study employed a 4x4 repeated-measures design with four groups and four assessment periods (pre-treatment, post-treatment, 6-month follow-up, and 18-month follow-up). The group studied consisted of subjects on sick leave identified in a nationwide health insurance scheme in Sweden. After inclusion, the subjects were randomized to one of four conditions, which were: (1) behavior-oriented physical therapy (PT); (2) cognitive behavioral therapy (CBT); (3) BM rehabilitation consisting of PT+CBT (BM); (4) a 'treatment-as-usual' CG. The treatments were given over a period of 4 weeks, PT and CBT on a part-time basis and BM on a full-time basis. Outcome variables were sick leave, early retirement, and health-related quality of life (measured using the Short Form Health Survey, SF-36). The results showed that the risk of being granted full-time early retirement was significantly lower for females in PT and CBT compared to the CG during the 18-month follow-up period. However, the total absence from work (sick listing plus early retirement) in days over the 18-month follow-up period was not significantly different in the CG compared to the treatments. On the SF-36, women in CBT and BM reported a significantly better health-related quality of life than women in the CG at the 18-month follow-up. No significant differences for men were found on the SF-36 scales. In conclusion, the results revealed gender differences in the outcome of the treatments and that the components of this BM program yielded as good results as the whole program.

Absenteeism↗

PubMed2001

Upper limb deficiencies in Swedish children--a comparison between a population-based and a clinic-based register.

OBJECTIVE: To validate information in the Swedish Register for Congenital Malformations (SRCM). METHODS: A comparison was made with a clinic-based register kept at the Limb Deficiency and Arm Prosthesis Centre (LDAPC). The report frequency and the quality of the information in SRCM were analysed. Cases were classified according to a detailed, clinically relevant classification, the ISO 8548-1:89 method. OUTCOME MEASURES: The completeness of SRCM was first estimated. The Kappa statistic was then used to assess the agreement between the two registers regarding individual categories and across all categories. RESULTS: For the period 1973-1987, we found 125 cases of upper limb reduction deficiencies (ULRD) in the clinic-based register, of which 117 was found in the national register. The completeness of SRCM was thus estimated to be 94% (95% confidence interval 89-98%). The inter-register agreement varied from almost perfect agreement in laterality of deficiency (Kappa 0.98) to substantial agreement in type and level of deficiency (Kappa 0.72-0.79). For specific levels of transverse deficiency, however, the agreement varied between -0.05 and 0.66. CONCLUSIONS: The results indicate that SRCM, with its calculated underestimation of 6%, can be used for studying the prevalence of ULRD in Sweden. However, as SRCM is a surveillance register, the quality of some information seems to be low, making detailed description of cases difficult. Use of the population register data for clinical purposes could therefore result in lower validity. Additional information and follow-up of specific cases are therefore recommended.

Arm↗

PubMed2001

Utilization of healthcare by very-low-birthweight infants during their first year of life.

New knowledge in perinatal medicine has resulted in increased survival of very-low-birthweight (VLBW) infants. After leaving hospital, the child is seen at regular medical check-ups, but there is often a persistent worry about the child which affects the family as a whole. This can lead to an increased utilization of healthcare. Our objective was therefore to describe the utilization of healthcare by VLBW infants during their first year of life and its relation to high-risk diagnoses in the neonatal period. The study group comprised 36 infants born at gestational ages of < or = 31 wk and with a birthweight of < or = 1500 g, and was compared with a control group of 36 full-term infants. Utilization of healthcare by the VLBW infants was higher than that by the control group in paediatric and ophthalmic outpatient clinics. The total number of contacts with healthcare was on average 38.7 versus 17.4. High-risk diagnoses in the neonatal period did not correlate with utilization of care, except for visits to the paediatric outpatient clinic, especially planned visits. Further studies focusing on how to support these families after leaving hospital are therefore needed.

Age Factors↗

PubMed2001

A systematic review of the peripheral analgesic effects of intraarticular morphine.

The analgesic effects of intraarticular morphine are controversial. To systematically evaluate the effects, we performed a review of the literature and a metaanalysis of the peripheral effects of morphine injected intraarticularly. Research databases were searched to identify articles in which peripheral analgesic effects of morphine were studied in patients undergoing arthroscopic knee procedures under local, regional, or general anesthesia. The review was performed on three issues: does morphine injected intraarticularly produce analgesia, is it a dose-dependent effect, and, if so, is the effect systemic or mediated via peripheral opioid receptors? Visual analog score (VAS) and analgesic consumption were studied during the early phase (0-2 h), intermediate phase (2-6 h), and late phase (6-24 h) postoperatively after injection of morphine intraarticularly. Metaanalysis of these effect variables was performed by the weighted-analysis technique, and the essential homogeneity assumption was tested by the chi(2) test. Forty-five articles could be identified in which the effects of morphine were studied in a prospective, randomized manner, and 32 of these studies included a placebo control. Pooled analyses of data from 19 studies suitable for metaanalysis showed an improvement in analgesia after morphine compared with placebo in the order of 12-17 mm on the VAS during all three phases of treatment. Studies with high quality scores showed somewhat smaller improvements. Total analgesic consumption could not be analyzed statistically, but the number of studies showing decreased analgesic consumption or no differences between groups was identical (six and six). No clear dose-response effect was seen when VAS was used as a measure of pain, but it was seen when area under the curve was used as a measure of pain. A systemic effect of peripherally-injected morphine was not possible to exclude because of the very limited data available. We conclude from this metaanalysis that intraarticularly administered morphine has a definite but mild analgesic effect. It may be dose dependent, and a systemic effect cannot be completely excluded.

Analgesics, Opioid↗

PubMed2001

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.

Adult↗

PubMed2001

Adjustment of incidence rates after an estimate of completeness and accuracy in registration of acute leukemias in a Swedish population.

Earlier studies have revealed undernotification of hematological malignancies in Swedish and other Cancer Registries. We present epidemiological data on AML, ALL and unspecified AL in adults diagnosed 1987-1992 in a well-defined population. Blast crises of CML were excluded. The Swedish Cancer Registry and Cause of Death Registry were compared and patient records reviewed for validation. When available, listings of pathology bone marrow reports and inpatient discharge diagnoses were utilized for casefinding. 260 cases of acute leukemias could be verified in a population of 663,135 adults, corresponding to a yearly incidence of 6.5/100,000. The median age of the patients was 69.2 years. 214 cases were AML, 38 ALL and eight unspecified AL. Undernotification in the Cancer Registry was found to be 15.4%, greater for AML and unspecified AL than for ALL. In addition the coding was not uniform, resulting in an incidence rate in adults of 5.3/100,000 for the Cancer Registry which is 18.5% lower than that of our study. A significant survival advantage was seen for notified patients. Combination of the Cancer Registry and Cause of Death Registry gave acceptable coverage, omitting only four patients. As the incidence of acute leukemias in our study is comparatively high, we hypothesize that underestimation of incidence and overestimation of survival are general problems for cancer registries.

Acute Disease↗

PubMed2000

Assessing the needs of patients in pain: a matter of opinion?

STUDY DESIGN: A prospective cohort study including patients with nonspecific spinal pain was performed. OBJECTIVES: To investigate whether the use of expert judgment in routine practice can provide a basis for reliable decision making concerning the need for intervention in patients with spinal pain and their ability to benefit from treatment. SUMMARY OF BACKGROUND DATA: A wide range of instruments and techniques are used to assess and treat patients with spinal pain. Many instruments are used without being clinimetrically tested. METHODS: A questionnaire concerning the patients' need of treatment and their potential to assimilate it was sent to experts in the health care arena: physicians, physical therapists, social insurance officers. The experts included were those connected with patients participating in a larger outcome study. Two cohorts of patients (sample 1, n = 217; sample 2, n = 257) were followed for 6 and 12 months, during which time the patients' health and work status were mapped. RESULTS: No acceptable agreement was found between any of the experts' ratings of patients' needs and potential for rehabilitation. Logistic regression showed that the experts' judgments were based almost solely on the age of the patient. The prediction analyses showed that the most consistent predictor of the patients' status at the 6-month follow-up assessment was the patients' own belief in the existence of effective treatments and their perceived ability for learning to cope with the condition. CONCLUSIONS: Expert judgment as exercised in routine practice cannot be used as basis for reliable decision making concerning the need of the patient with spinal pain for intervention and the patient's ability to benefit from treatment.

Adult↗

PubMed2000

Direct and indirect time spent on care of dental trauma: a 2-year prospective study of children and adolescents.

The aim was to account for the total time spent by professional care-givers (direct time) and by patients and companions engaged as support and help (indirect time) to treat and otherwise attend to children and adolescents with dental trauma to primary and permanent teeth. The study was based on a random sample of 192 children and adolescents with dental traumas reported to an insurance company and prospectively followed up by telephone interviews over a period of 2 years after the trauma episode. On average, direct time represented 16% of total time for all visits for dental trauma to permanent teeth and 11% for trauma to primary teeth. The most extensive type of indirect time was transport time, which took up 30% of the total time spent on injuries to permanent teeth and 36% for injuries to primary teeth. Multiple regression analysis of the impact of dental and demographic injury variables on the time variables showed that complicated trauma was associated with extended time, direct as well as indirect, for permanent and primary teeth injuries. Our estimate of the average relative increase in total time spent by patients and companions in cases of complicated injury to permanent teeth was 117% (95% confidence interval [CI], 52-211) for patients and 112% (95% CI, 42-217) for companions. For transport time a strong predictor was access to a dental clinic near the place of residence. Lack of access could extend the average transport time by 180% (95% CI, 80-335) for patients and 163% (95% CI, 67-317) for their companions in cases of injuries to primary teeth.

Absenteeism↗

PubMed2000

Treatment, long-term outcome and prognostic variables in 214 unselected AML patients in Sweden.

With the aim of describing an unselected series of acute myeloid leukaemias (AML) in adults, patients diagnosed 1987-1992 in the Orebro region of central Sweden were reviewed by investigating hospital records. By utilizing: (1) The Swedish Cancer Registry, (2) The Cause of Death Registry, (3) listings of pathology bone marrow reports and (4) listings of inpatient discharge diagnoses, we attempted to find all patients. Among secondary AML, only blast-crises of CML were excluded. A total of 214 cases of AML with a median age of 69.5 years were verified corresponding to a mean yearly incidence in adults of 5.4/100 000. Of all patients, 56% had received 'high-dose' induction treatment, 28% 'low-dose' treatment and 16% no cytostatic treatment. Median survival for all patients was 5.8 months and the probability of survival at 5 years was 9.3%. The 120 'high-dose' treated patients had a total CR rate of 67%, median CR duration 10.1 months and median survival 11.4 months. Age, LDH and kidney function were found to be independent prognostic variables for survival. The inclusion of patients unreferred from district hospitals makes this study unique as an example of unselected AML.

Acute Disease↗

PubMed2000

Association between expression of reproductive seasonality and alleles of the gene for Mel(1a) receptor in the ewe.

To determine whether a link exists between reproductive seasonality and the structure of the gene for melatonin receptor Mel(1a), the latter was studied in two groups of Mérinos d'Arles (MA) ewes previously chosen for their genetic value, which took into account their own out-of-season ovulatory activity adjusted by environmental parameters and that of their relatives. The genomic DNA of 36 ewes found regularly cycling in spring (group H) and that of 35 ewes never cycling in spring (group L) during the 2-3 yr before the present study was prepared, and the cDNA corresponding to almost all exon II was amplified and checked for the presence of MnlI restriction sites. The presence (+) or absence (-) of an MnlI site at position 605 led to genotypes "++", "+-", and "--", whose frequencies differed significantly (P < 0.001) between the H and L groups: 52.8%, 47.2%, and 0% vs. 28.5%, 42.9%, and 28.5%, respectively. Sequencing of exon II cDNA in group L ewes with genotype -- showed the presence of only one allele - with 4 mutations, while that in ewes with genotype ++ showed different types of alleles unrelated to the H or L groups. These + alleles exhibited a combination of 1 to 7 of the 8 mutations recorded in the part of exon II studied. The genotyping of 29 ewes from the more seasonal Ile-de-France breed indicated that 38% of animals had a -- genotype and exhibited the same mutations as in the MA ewes. Finally, a comparison of (125)I-melatonin binding to membrane preparations of pars tuberalis showed a lower number of binding sites (P < 0. 0005) in MA ewes with genotype ++ than in those with genotype -- (43. 2 +/- 4.4 vs. 75.4 +/- 8.4 fmol/mg protein in genotype ++ and genotype --, respectively). In conclusion, the data show an association between genotype -- for site MnlI at position 605 and seasonal anovulatory activity in MA ewes.

Alleles↗

PubMed2000

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.

Abortion, Spontaneous↗

PubMed2000

Duplications and defects in the CYP2A6 gene: identification, genotyping, and in vivo effects on smoking.

In humans, 80% of nicotine is metabolized to the inactive metabolite cotinine by the enzyme CYP2A6, which can also activate tobacco smoke procarcinogens (e.g., 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone). Previously, we demonstrated that individuals who are nicotine-dependent and have defective CYP2A6 alleles (*2, *3) smoked fewer cigarettes; however, we recognize that the genotyping method used for the CYP2A6*3 allele gave a high false-positive rate. In the current study we used improved genotyping methods to examine the effects of the defective CYP2A6*2 and CYP2A6*4 alleles on smoking behavior. We found that those with the defective alleles (N = 14) smoked fewer cigarettes per day than those homozygous (N = 277) for wild-type alleles (19 versus 28 cigarettes per day, P <.001). In addition, we identified a duplicated form of the CYP2A6 gene, corresponding to the gene deletion CYP2A6*4 allele, developed a genotyping assay, assessed the gene copy number, and examined its prevalence in Caucasian smokers (N = 296). We observed an ascending rank order for plasma cotinine and breath carbon monoxide levels (an index of smoke inhalation) in individuals with null (CYP2A6*2 and CYP2A6*4) alleles (N = 14), those homozygous for wild-type (CYP2A6*1/*1) alleles (N = 277), and those with our newly identified CYP2A6 gene duplication (N = 5). The phenotype, as determined by plasma nicotine/cotinine ratios, had a descending rank order for these three genotype groups that did not reach significance. Although further characterization is required for the duplication gene variant, these results extend our previous findings and suggest a substantial influence of CYP2A6 genotype and phenotype on smoking behavior.

Adolescent↗

PubMed2000

Epidemiology of ectopic pregnancy during a 28 year period and the role of pelvic inflammatory disease.

OBJECTIVES: We analysed the epidemiology of ectopic pregnancy (EP) during a 28 year period, 1970-97, using methods applicable to ecological studies in order to test the hypothesis that a reduction of pelvic inflammatory disease (PID) will be associated with a decrease of EP. METHODS: Hospital records of patients aged 15-54 admitted to our department of gynaecology were reviewed for EP and PID for the period 1 January 1970 to 31 December 1997. EP for the period 1970-4 was based on available statistics. The total number for EP was 1270 and for PID 2559. The total population for the catchment area was 100,000-120,000 during the study period. Incidences were age standardised and calculated using official population statistics to represent the average female population in the five 5 year periods 1970-4, 1975-9, 1980-4, 1985-9, 1990-4, and in each of the consecutive years 1995, 1996, and 1997. Incidences for EP were calculated per 1000 women and per 1000 pregnancies while those for PID per 1000 women. National statistical data of EP were available for 1975-94 and were used for comparison with the local study. RESULTS: The EP incidences increased from 7.7 per 1000 pregnancies in the first 5 year period to 13.4 in the second, and continued to rise for another decade reaching the peak figures of 16.6 in 1985-9--that is, more than a twofold increase. Since then and to 1997 the EP incidence has decreased by 30%. PID admissions increased during the study period from 2.7 per 1000 women in the first 5 year period to 3.2 in the second. From then on they continuously decreased and reached a low of 0.5 in 1997. The greatest changes occurred in women < or = 24 years of age. The peak incidence for this age group was 7.7 in 1975-9, and the lowest was 0.4 per 1000 women in 1996. The greatest reduction of EPs was noted for women < or = 24 years old, from a high of 10.0 in 1975-9, coinciding with the peak incidence of PID, to a low of 4.0 in 1997, a reduction of 58.4%. The incidence of EP was two to three times higher in women > or = 25 years old, most obvious in those > or = 30 years, with peak figures of 20.9 per 1000 pregnancies in 1985-9, and 13.9 in 1997, a reduction of 33.4% and the lowest figures for the past 23 years. For women aged 25-29 years the incidence peaked in the previous 5 year period 1980-4--that is, one 5 year period later than for those < or = 24 years, which we interpret as cohort effects in relation to PID. CONCLUSIONS: Reduction of PID was strongly associated with a decline of EP. The decline was greater and immediate for women < or = 24 years old, than for those > or = 25 years. The two to three times higher EP incidence in women > or = 25 years of age was most probably due to a cohort effect as the peak of PID occurred a decade earlier in women < or = 24 years old. Prevention of PID may not only reduce EP but also reduce adverse effects on tubal patency.

Adolescent↗

PubMed1999

Impact of intraocular pressure regulation on visual fields in open-angle glaucoma.

OBJECTIVE: To investigate the correlation of different parameters of intraocular pressure (IOP) to visual field decay in open-angle glaucoma. DESIGN: Analysis of visual field decay during a prospective, randomized clinical trial comparing primary laser trabeculoplasty with medication. PARTICIPANTS: Of a total of 82 included eyes in 82 patients with newly detected high-pressure open-angle glaucomas, 76 (55 capsular, 21 simple) fulfilled the 2-year follow-up with the stated number of reliable visual field examinations and were included in this analysis. INTERVENTION: Automated perimetry and a daytime IOP curve were taken every second month during the 2-year follow-up. MAIN OUTCOME MEASURES: Six IOP parameters were evaluated and correlated to visual field outcome. The subgroups with the two types of glaucoma (capsular and simple) were analyzed separately. RESULTS: Visual field decay showed greater correlation to IOP variation (range and peak) and mean IOP than IOP at start or degree of IOP reduction. The relation between mean IOP and visual field decay in the whole group was not quite linear, with more decay at higher IOP levels. The association between IOP regulation and visual field decay was most pronounced in capsular glaucoma, whereas the results in the small group of simple glaucomas were inconclusive. CONCLUSIONS: Visual field prognosis in high-pressure open-angle glaucoma, essentially capsular glaucoma, is better in patients with smaller IOP variation and poorer in patients with high mean IOP.

Aged↗

PubMed1999

Comparison of dust sampling methods in Estonia and Sweden--a field study.

The purpose of this field study was to compare an Estonian dust sampling method, a method also used in other former East Block countries, with a Swedish method and to estimate inter-method agreement with statistical analyses. The Estonian standard method (ESM), used to assess exposure in Estonia since the early 1950s, is based on a strategy where air samples are collected for 10 minutes every hour over a full shift. This method was compared to a Swedish standard method (SSM), a modified NIOSH method, comparable to international standards, where one air sample is collected during a full shift. The study was carried out at a cement plant that in the beginning of the 1990s was subjected to an epidemiological study, including collection of exposure data. The results of the analysis from 31 clusters of parallel samples of the two methods, when dust consisting of Portland cement was collected, showed a relatively weak correlation between the SSM and the ESM, ri = 0.81 (Pearson's intra-class correlation coefficient). A conversion factor between the two methods was estimated, where SSM is 0.69 times ESM and the limits of agreement are 0.25 and 1.84, respectively. These results indicate a substantial inter-method difference. We therefore recommend that measurements obtained from the two methods should not be used interchangeably. Because the present study is of limited extent, our findings are confined to the operations studied and further studies covering other exposure situations will be needed.

Air Pollutants, Occupational↗

PubMed1999

Protective effect of breastfeeding: an ecologic study of Haemophilus influenzae meningitis and breastfeeding in a Swedish population.

BACKGROUND: In Orebro County, Sweden, a 2.5-fold increase in the incidence of Haemophilus influenzae (HI) meningitis was found between 1970 and 1980. In a case-control study of possible risk factors for invasive HI infection conducted in the same area, 1987-1992, breastfeeding was found to be a strong protective factor. MATERIAL AND METHODS: In order to study the relation between incidence rates of HI meningitis between 1956-1992 and breastfeeding rates in the population an ecologic study was performed. RESULTS: A strong (negative) correlation between breastfeeding and incidence of HI infection 5 to 10 years later (rho(xy) (s) approximately -0.6) was seen, whereas no relation seems to exist for the time lag 15 years and beyond. The correlation for contemporary data was intermediate. There were similar results for the breastfeeding proportions at 2, 4 as well as 6 months of age. DISCUSSION: Our ecologic data are consistent with results from our case-control study. The time-lag for the delayed effect on the population level could be estimated although sparse data make the estimates vulnerable to sampling fluctuations. Limitations with ecologic studies are discussed. CONCLUSION: There seems to be an association between high breastfeeding rate in the population and a reduced incidence of HI meningitis 5 to 10 years later. These results do have implications on strategies for breastfeeding promotion, especially in countries where Hib vaccination is too costly and not yet implemented.

Adolescent↗

PubMed1999

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).

Adult↗