Population-based consultation patterns in patients with shoulder pain diagnoses.

BACKGROUND: To assess the annual consultation prevalence and new onset consultation rate for doctor-diagnosed shoulder pain conditions. METHODS: We identified all residents in the southernmost county in Sweden who received a shoulder pain diagnosis during 2006 (ICD-10 code M75). In subjects who did not consult due to such disorders during 2004 and 2005, we estimated the new onset consultation rate. The distribution of specific shoulder conditions and the length of the period of repeated consultation were calculated. RESULTS: Annual consultation prevalence was 103/10,000 women and 98/10,000 men. New onset consultation rate was 80/10,000 women (peak in age 50-59 at 129/10,000) and 74/10,000 men (peak in age 60-69 at 116/10,000). About one fifth of both genders continued to consult more than three months after initial presentation, but only a few percent beyond two years. Rotator cuff--and impingement syndromes were the most frequent diagnoses. CONCLUSION: The annual consultation prevalence for shoulder pain conditions (1%) was similar in women and men, and about two thirds of patients consulted a doctor only once. Impingement and rotator cuff syndromes were the most frequent diagnoses.

Reproductive outcome in a cohort of male and female rubber workers: a registry study.

PURPOSE: To investigate whether blue-collar employment in the Swedish rubber industry from 1973 onwards had a negative impact on reproductive health. METHODS: Pairs of mother and child, and triads of father-mother-child were obtained through linkage of a cohort of 18,518 rubber factory employees with the Swedish Population Registry. Birth outcomes were obtained from the Medical Birth Register for 17,918 children. For each child, parental employment as blue-collar rubber worker during the pregnancy and sperm maturation period was obtained from work-place records. Children to female food industry workers, in all 33,256, constituted an external reference group. RESULTS: The sex ratio was reversed, with odds ratio (OR) for having a girl was 1.15 (95% CI 1.02, 1.31) when the mother was exposed. When both parents were exposed, the OR was even higher, 1.28 (95% CI 1.02, 1.62). An increased risk of multiple births was observed when both parents were exposed, with OR 2.42 (95% CI 1.17, 5.01). Children with both maternal and paternal exposure had a reduced birth weight compared to the external reference cohort. After adjustment for smoking (available for births from 1983 onwards), ethnicity and sex, the difference between children (singletons, live births) with maternal and paternal exposure and external referents was -142 g (95% CI -229, -54). The adjusted OR for having a small-for-gestational-age child was 2.15 (95% CI 1.45, 3.18) when the mother was a rubber worker during the pregnancy. CONCLUSION: There were clear indications that reproductive outcome was adversely affected in rubber workers. The findings warrant further investigation with refinement of exposure indices and inclusion of other endpoints of reproductive health.

Incidence of hand eczema in female Swedish hairdressers.

OBJECTIVE: To estimate the occurrence of hand eczema in hairdressers in Sweden. METHODS: The occurrence of hand eczema was estimated in a Swedish longitudinal retrospective cohort study including all female graduates from vocational schools for hairdressers from 1970 to 1995. A stratified sample from the general population acted as controls. A self-administered questionnaire including questions on the occurrence of hand eczema, skin atopy, working periods and number of hair treatments performed per week was sent to the participants. Incidence rate ratios (IRRs) of hand eczema were estimated. RESULTS: The incidence rate of hand eczema in hairdressers was 23.8 cases/1000 person-years, whereas in hairdressers who were aged <25 years it was 37.1/1000 person-years. The corresponding IRR for hairdressers compared with controls was 2.5 (95% confidence interval (CI) 2.2 to 2.8), and that for younger hairdressers was 3.1 (95% CI 2.6 to 3.5). The mean age at onset of hand eczema was 21.6 years for hairdressers and 21.2 years for controls. The 1-year prevalence of hand eczema was 18.0% for hairdressers and 12.1% for controls. A large number of hair treatments involving exposure to skin irritants and sensitisers were reported. The incidence rate of hand eczema was higher among individuals with a history of childhood eczema, both for hairdressers and for controls, giving an (age-adjusted) IRR of 1.9 and 2.2, respectively. The attributable fraction of hand eczema from skin atopy was 9.6%. A synergistic effect of skin atopy and hairdressing was found on the occurrence of hand eczema. The relative excess risk due to interaction was 1.21 (95% CI 0.21 to 2.21; p = 0.01). CONCLUSION: Hairdressers are highly exposed to skin-damaging substances. The self-reported incidence of hand eczema was substantially higher in female hairdressers than in controls from the general population and than that found previously in register-based studies. For many individuals, onset of hand eczema occurs early in life. Only about 10% of the hand eczema cases among hairdressers would be prevented if no one with skin atopy entered the trade.

Late effects of low blood lead concentrations in children on school performance and cognitive functions.

BACKGROUND: Although it is known that lead is a neurotoxin that negatively impacts cognitive functions at low blood concentrations (B-Pb), little is known about the impact of early exposure on later cognitive functions. OBJECTIVES: This study assesses the effects of very low lead exposure in early childhood on teenage cognitive performance. METHODS: Using data collected between 1978 and 2007, we analyzed B-Pb (median 30 µg/L; six-fold decrease over time) in 3176 Swedish children (age 7-12). School performance in grade 9 (age 16; boys and girls) and over-all IQs measured during conscription examinations (age 18-19; mainly boys) were obtained from registers. In multivariate models, potential confounders (age at blood sampling, sex, parents' education, family economy, and country of birth of child and parents) and effect modifiers (socioeconomic; father's IQ at conscription examination) were included. RESULTS: There were statistically significant adjusted negative associations between school performance (Grades up to 1991: P<0.0001; Merits 1992-2007:P<0.0001) and IQ (P=0.03) and B-Pb. The dose-response relationships were non-linear. Effects were more pronounced for B-Pb≤50 µg/L than for higher levels. In the B-Pb range 5-50 µg/L, the average IQ loss corresponded to about 5 IU. There was no significant effect modification associated with socioeconomic factors. CONCLUSIONS: Lead causes neurotoxic effects at very low exposures (B-Pb<50 µg/L) in childhood and these effects remain for many years.

Risk factors for cerebrovascular deaths in patients operated and irradiated for pituitary tumors.

Vascular mortality, especially cerebrovascular disease (CVD), are the most pronounced cause of mortality in women with hypopituitarism. In a cohort of 342 patients operated and irradiated for pituitary tumors, 31 died from CVD (CVD patients) between 1952 and 1996. The study assessed whether the radiation regimens and duration of symptoms of hypopituitarism before operation differed between the 31 CVD patients and the 62 matched patients from the same cohort who had not died from CVD (control patients). Furthermore, the infarction/hemorrhage ratio, type of clinical stroke syndrome, and time to death after stroke were investigated in the CVD patients and in matched controls from the general population who had died from CVD (population controls). No significant differences in maximum or centrally absorbed dose, maximum or central biological equivalent dose, field size, or number of fraction were recorded between CVD and control patients. A significant difference in the duration of symptoms of hypopituitarism before operation was recorded, but only in women (P = 0.01). There were no significant differences in the infarction/hemorrhage ratio (P > 0.3) of lacunar or posterior circulation syndrome compared with middle cerebral artery syndrome with cortical features (P = 0.22) or the proportion of patients who died within the first month after stroke onset (60% vs. 59%, respectively) between CVD patients and population controls. In conclusion, no significant effect on CVD deaths could be detected for any radiation parameter. A long history of unsubstituted pituitary insufficiency may be a contributing factor to the very high CVD mortality among women. There were no indications of significant differences in type of stroke, clinical stroke syndromes, or stroke fatality between the CVD patients and the population controls.

Doubled mortality rate in irradiated patients reoperated for regrowth of a macroadenoma of the pituitary gland.

BACKGROUND: Reduced life expectancy has been shown in patients with hypopituitarism, mainly caused by cardiovascular diseases. A major cause of hypopituitarism is pituitary adenomas, and radiotherapy may be employed as a treatment modality to reduce the post-operative regrowth rate of these tumours. Recently, we showed that in patients with craniopharyngiomas, tumour regrowth foreshadowed a fourfold risk increase for death. For patients with pituitary adenomas, the impact of regrowth on life expectancy is, however, not known. OBJECTIVE: To assess the impact of a reoperation due to a regrowth of a pituitary macroadenoma on mortality, taking into account other candidate prognostic factors. DESIGN AND PATIENTS: In 281 patients with operated and irradiated macroadenomas, excluding acromegaly and Cushing's disease, 35 patients had a regrowth (median follow-up 16.6 years). Possible risk factors for tumour regrowth were investigated by Cox regression models. RESULTS: For tumour regrowth, age, calendar time at primary surgery, gender and extension of tumour growth had no statistically significant impact. For younger patients, the proportion of regrowths was higher, but after age-stratified Cox regression analysis only regrowth was shown to have a significant impact on mortality, with a more than doubled mortality risk for patients with tumour regrowth as compared with the non-regrowing tumour patients (hazard ratio=2.24, P<0.001). This finding was corroborated by cohort analyses using the general population as an external comparison group. CONCLUSION: Among patients with irradiated pituitary macroadenomas, excluding acromegaly and Cushing's disease, a doubled mortality rate was observed for those reoperated for tumour regrowth as compared with patients with non-regrowing tumours.

Cytogenetic and morphologic subgroups of myelodysplastic syndromes in relation to occupational and hobby exposures.

OBJECTIVES: This study investigated the association between occupational and hobby exposure and the risk of myelodysplastic syndromes (MDS) while focusing on differential patterns of clonal chromosome aberrations and morphologic subgroups. METHODS: A case-referent study was conducted with 330 MDS patients investigated cytogenetically in 1976-1993 (cases) and matched referents. Telephone interviews with either the person or a next-of-kin were used. The participation rate of the cases and referents was 85% and 60%, respectively. Information was obtained from the next-of-kin more often for the cases (88%) than for the referents (26%). Occupational hygienists assessed the exposure using interview data on worktasks and hobbies. Associations with disease risk were evaluated for 10 exposures with a logistic regression analysis. RESULTS: The investigated exposures were generally not associated with cytogenetically abnormal MDS. Effect estimates for specific cytogenetic or morphologic subgroups were generally imprecise. Occupational exposure to extremely low-frequency magnetic fields (EMF) was associated with MDS with a normal karyotype [odds ratio (OR) 2.0, 95% confidence interval (95% CI) 1.0-4.0]. The exposure-response association was consistent for intensity but inconclusive for duration. A decreased risk was observed for MDS, irrespective of karyotypic pattern, among farmers and farmhands (OR 0.53, 95% CI 0.35-0.81). CONCLUSIONS: Cytogenetically abnormal MDS was generally not associated with occupational or hobby exposure to known or suspected genotoxic agents. However, exposure prevalences and intensities were low for several agents. An association was suggested between occupational exposure to EMF and MDS with a normal karyotype. Biases due to differential information quality and selective participation cannot be ruled out.

Cancer incidence and mortality in Swedish sterilant workers exposed to ethylene oxide: updated cohort study findings 1972-2006.

OBJECTIVES: To assess whether cancer incidence, mainly from lymphohaematopoietic tumours and breast cancer, and mortality were increased in a cohort of Swedish sterilant workers exposed to low levels of ethylene oxide (EtO), updated with 16 more years of follow up. METHODS: The mortality and cancer incidence 1972-2006 experienced by a cohort of 2,171 male and female workers employed for at least one year in two plants producing medical equipment sterilised with EtO were investigated. Individual cumulative exposure to EtO was assessed by occupational hygienists. Cause-specific standardized rate ratios were calculated using the regional general population as a comparison for mortality (SMR) and cancer incidence (SIR). Internal Poisson-regression analyses were performed for selected causes. RESULTS: The median cumulative exposure to EtO was 0.13 ppm-years. The overall cancer incidence was close to unity (SIR 0.94, 95% CI 0.82-1.08). Eighteen cases of lymphohaematopoietic cancer were observed (SIR 1.25, 95% CI 0.74-1.98). A healthy worker effect was indicated from a significantly decreased overall mortality and mortality from cardiovascular diseases. Internal analyses found significantly increased rate ratios for breast cancer for the two upper quartiles of cumulative exposure as compared to the lowest 50% of the cohort (IRR 2.76, 95% CI 1.20-6.33 and IRR 3.55, 95% CI 1.58-7.93). CONCLUSIONS: The findings from this updated study indicate limited or low risks for human cancer due to occupational exposure from ethylene oxide at the low cumulative exposure levels in this cohort. However a positive exposure-response relation with breast cancer was observed though.

Mortality and cancer incidence in cohorts of Swedish fishermen and fishermen's wives: updated findings.

OBJECTIVES: Intake of fish is an important source for many essential substances, such as n-3 PUFA. However, certain fish also contains relatively high levels of PCBs and dioxins. In Sweden, the concentrations of these compounds are higher in fatty fish caught at the east coast as compared to fish from the west coast. The aim of the present study was to assess cancer incidence and mortality pattern among cohorts with a relatively high intake of locally caught fish from the Swedish coasts. METHODS: Cohorts of fishermen and fishermen's wives from the Swedish west and east coasts were established. Cancer incidence and mortality patterns were assessed up to year 2002, and cause-specific standardised incidence (SIRs) and mortality (SMRs) ratios were calculated. RESULTS: Low rates for overall mortality were observed in the two cohorts from the west coast. We observed lower than expected rates especially for respiratory and cardiovascular diseases. Incidence of colon cancer was lower than expected among the east coast fishermen and higher than expected among the east coast wives. Consistently increased incidence of lip cancer, and an elevation of the squamous cell skin cancer incidence, was seen in the fishermen cohorts. CONCLUSIONS: The low rates for overall mortality and cancer incidence, and low death rates for major diseases, and the low colon cancer incidence, indicates a positive impact of high dietary fish consumption, and health benefits from a highly physically active work environment for the fishermen. Sun exposure as an occupational hazard among fishermen should not be neglected.

Epidemiological evaluation of cytogenetic biomarkers as potential surrogate end-points for cancer.

Various occupational exposures have been monitored by chromosomal aberrations, sister chromatid exchanges and micronuclei in peripheral blood lymphocytes. During the last decade, epidemiological studies have evaluated whether any of these markers foreshadows cancer risk. Results from Nordic, Italian and Czech cohorts support an approximately twofold cancer risk among subjects with high frequencies of chromosomal aberrations, but no such association was seen for any of the other biomarkers. The estimated attributable proportion of high frequencies of chromosomal aberrations for overall cancer risk is 0.25, which gives a quantitative estimate of the chromosomal aberration assay as a surrogate endpoint of cancer. The results from the different cohort studies are contradictory in terms of whether or not the predictive value of the chromosomal aberration assay for cancer is differential with respect to occupational exposure to clastogens. Genetic susceptibility factors are known to affect the frequency of chromosomal aberrations in peripheral blood lymphocytes. It is quite possible that such factors might also affect the frequency of chromosomal aberrations directly or might modify the impact of exposures to clastogen. There is no other biomarker for general cancer risk that is applicable to healthy subjects from the general population with such a high attributable proportion. However, at present only a simplified and tentative model can be proposed for the role of the chromosomal aberration marker in the pathogenesis of cancer.

The incidence of respiratory symptoms in female Swedish hairdressers.

BACKGROUND: Airway diseases in hairdressers are a concern. The objective of this investigation is to evaluate the risk for three respiratory symptoms, wheeze, dry cough, and nasal blockage, in hairdressers. METHODS: A questionnaire on respiratory symptoms, atopy, smoking, and work history was answered by 3,957 female hairdressers and 4,905 women from the general population as referents. Incidence rates (IR) and incidence rate ratios (IRRs) for the three symptoms were estimated. RESULTS: The IRs of all three studied symptoms were higher in the hairdressers compared with the referents. Smoking modified the effects of cohort affiliation for all three symptoms; the combined effect from hairdressing work and smoking was less than expected. In addition, the effect of cohort affiliation for wheeze was also modified by atopy, and the effect of cohort affiliation for nasal blockage was also modified by calendar year. CONCLUSIONS: Hairdressing work was associated with increased incidences of respiratory symptoms. Smoking had a negative modifying effect.