The Oslo Health Study: The impact of self-selection in a large, population-based survey

Bone mineral density in ethnic Norwegians and Pakistani immigrants living in Oslo--The Oslo Health Study

Bone mineral density (BMD, grams per square centimeter) is scarcely studied in immigrants from the Indian subcontinent. Pakistani immigrants in Oslo, Norway, have a very high prevalence of vitamin D deficiency. Thus, it is of great interest to compare BMD between Pakistani immigrants and ethnic Norwegians in Oslo. The comparison was done with and without adjustment for skeletal size, and we examined whether known risk factors explained possible differences in bone density between these two ethnic groups. BMD was measured at the distal and ultra-distal forearm site in a random sample of the participants in the Oslo Health Study by single energy X-ray absorptiometry (SXA). One hundred and seventy-three Pakistani-born subjects (71 women, 102 men) and 1,386 Norwegian-born subjects (675 women, 711 men) aged 30, 40, 45 and 59/60 years, living in Oslo, were included in the analysis. To account for variation in skeletal size, we computed height-adjusted BMD values, BMD/height (grams per cubic centimeter), and volumetric bone mineral apparent density (BMAD, grams per cubic centimeter). We found no differences in distal or ultra-distal forearm BMD between Pakistanis and Norwegians in either women or men. We found, however, higher values in Pakistani men when BMD was height-adjusted (2% higher in distal sites and 5% in ultra-distal sites). We also found higher bone mass values (both distal and ultra-distal) in Pakistani women and men than in their Norwegian counterparts when volumetric measures, such as BMD/height (7%-8% higher in women, 6%-7% in men) and BMAD (6% higher in women, 8% in men), were used. In a regression model that included ethnicity, anthropometry and lifestyle factors, BMD was higher in Pakistani men than in Norwegian men, but not in women. We conclude that Pakistanis living in Oslo have similar BMD to ethnic Norwegians, but they have higher volumetric bone mass values. When we adjusted for confounders we found higher BMD values in Pakistani men than in Norwegian men.

Ethnicity and sex are strong determinants of diabetes in an urban Western society: implications for prevention

AIMS/HYPOTHESIS

This study was conducted to investigate the prevalence of diabetes and its association with ethnicity and sex, to identify subgroups at special risk.

METHODS

We performed a population-based cross-sectional survey of 30- to 67-year-olds in an area of Oslo with low socio-economic status, and collected data using questionnaires, physical examinations and serum analyses for the 2,513 participants (attendance rate 49.3%).

RESULTS

In the age group 30-59 years, mean BMI was 28.5 (95% CI: 27.5-29.6) for South Asian women, 26.1 (25.9-26.4) for Western women, 26.7 (26.1-27.4) for South Asian men and 27.2 (26.9-27.5) for Western men. The diabetes prevalence rates were 27.5% (18.1-36.9) for South Asian women, 2.9% (1.9-3.4) for Western women, 14.3% (8.0-20.7) for South Asian men and 5.9% (4.2-7.5) for Western men. The age-adjusted odds ratio (OR) for diabetes for women vs men was 1.9 (0.9-4.1) for South Asians, and 0.4 (0.3-0.6) for the Western population (p<0.001). The age-adjusted OR for diabetes for South Asians vs Westerners was 11.0 (5.8-21.1) for women and 3.0 (1.6-5.4) for men, and after adjustment for WHR the ORs were 7.7 (3.9-15.3) for women and 2.6 (1.4-4.9) for men. After additional adjustments for physical activity, education, body height and fertility for women, the OR was 6.0 (2.3-15.4) for women and 1.9 (0.9-4.0) for men.

CONCLUSIONS/INTERPRETATION

The alarmingly high prevalence of diabetes among South Asian women in Norway needs further investigation, as it has considerable public health implications. Ethnic differences in OR for diabetes persisted after adjustment for age, adiposity, physical activity and education. These differences were still present for women after additional adjustment for body height and fertility.

The impact of injecting drug use status on hepatitis C-related referral and treatment

More than 160,000 people are living with chronic hepatitis C virus (HCV) infection in Australia, however, rates of medical treatment are low. The aim of this study is to examine uptake and predictors of HCV-related health care services among a community-based sample of people with HCV. A self-administered questionnaire was completed by a largely non-clinical sample of 362 women and 308 men with HCV living in the state of Victoria. Analyses were performed according to injecting drug use (IDU) status: no history of injecting (non-IDUs), previous history of injecting (past-IDUs) and current (within the last 12 months) history of injecting (current IDUs). Bivariate and multivariate predictors of referral to a specialist liver clinic were also assessed. Fifty-one percent of participants were current IDUs, 33% past-IDUs and 16% non-IDUs. Fifty-two percent of women and 37% of men reported ever being referred to a specialist liver clinic and 18% of women and 20% of men reported previous HCV antiviral therapy. Although there were many factors related to an increased likelihood of referral (e.g. being female, longer time since diagnosis, longer consultation time at diagnosis, experiencing HCV-related symptoms), multivariate analysis revealed that not being a current IDU and seeing a GP specifically for HCV were the most important independent predictors of referral. For those who had been referred to a liver clinic, a history of IDU was associated with a lower chance of receiving antiviral therapy. IDU status is associated with both referral and treatment. The extension of HCV treatment services to involve GPs and drug and alcohol practitioners should be explored as models to improve access to antiviral therapy.

Gender differences in factors associated with psychological distress among immigrants from low- and middle-income countries--findings from the Oslo Health Study

OBJECTIVE

Despite the high rate of migration from low- and middle-income countries to high-income countries, there is still a lack of comprehensive studies of gender-specific differences in psychological distress in a diverse group of immigrants. We compared psychological distress between male and female immigrants from low- and middle-income countries living in Oslo, and identified factors associated with distress for men and women, separately.

METHOD

A cross-sectional survey with self-administered questionnaires was conducted among 1536 immigrants from low- and middle-income countries living in Oslo. The Hopkins Symptom Checklist (HSCL-10) was used to measure psychological distress. Data on their sociodemographic characteristics, negative and traumatic life events, and social integration and possible discrimination in the Norwegian society were also collected.

RESULTS

One-fourth of the study population was found to be psychologically distressed, with almost equal levels among men and women. Lack of salaried job and recent negative life events were independently associated with psychological distress for both genders. Furthermore, experience of denial of job and past traumatic experiences were other associated negative factors among men, while visits made by Norwegians appeared as a protective factor against distress among men. Older age, Middle East background, living without a partner, and experiencing denial of housing were other associated negative factors among women.

CONCLUSION

Our findings show that, except for adverse living conditions, there are gender differences with regard to factors associated with psychological distress among immigrants living in Oslo. Such gender issues are relevant for assisting immigrants in the integration process as well as for future research in migration and health.

Use of psychotropic drugs in an urban adolescent population: the impact of health-related variables, lifestyle and sociodemographic factors?The Oslo Health Study 2000-2001

AIMS

The aims of the study were to examine use of psychotropic drugs among 15-16 years old adolescents and to study the association between use of drugs and health-related, lifestyle and sociodemographic factors.

MATERIAL AND METHODS

The youth part of the Oslo Health Study 2000-2001 included all individuals in 10th grade in Oslo County, Norway. A total of 3612 boys and 3695 girls, participated, giving a participation rate of 86.1% for boys and 90.6% for girls. All students filled in two self-administered questionnaires on various health behaviours, including use of medicines. Persons who reported use of hypnotics, anxiolytics and/or antidepressants during the last 4 weeks were defined as users. Data were analysed using bivariate and multivariate techniques.

RESULTS

In all, 3.4% boys and 3.7% girls had used one or more psychotropic drugs during the last 4 weeks. Multivariate analyses revealed that mental disorders, seeing a psychologist/psychiatrist and use of prescription analgesics were significantly associated with the use of psychotropic drugs for both genders. Smoking, exposure to violence and lower education plans were registered as important factors for males only, whilst for females the factor 'one parent not working' was registered as significant.

CONCLUSION

The proportion of psychotropic drug users in this young population was relatively low, under 4% and similar for males and females. Analyses of various factors associated with use of psychotropic drugs show that health, physical and mental, are the most important factors, and that lifestyle and socio-economic factors are of minor importance.

Musculo-skeletal pain among 40- and 45-year olds in Oslo: differences between two socioeconomically contrasting areas, and their possible explanations

BACKGROUND: The objective of the study was to compare the prevalence and severity of musculo-skeletal pain between two socioeconomically contrasting areas in Oslo, Norway, and to explore possible explanatory factors. METHODS: Questionnaire survey, carried out as part of The Oslo Health Study in 2000-2001. Data from 821 persons (40 and 45 year old) living in a less affluent inner city area (called east) were compared with 854 persons living in an affluent area of the city (called west). Bivariate comparisons (chi square test) and multiple regression analyses were performed to investigate differences between the samples. RESULTS: 61 % in east and 56 % in west (p < 0.05) reported pain/stiffness in muscles/joints during the last four weeks. 30 % in east versus 19 % in west (p < 0.001) reported extensive pain. The between area difference in extensive pain was partially explained by physical inactivity, mental health problems and being of non-Western origin. CONCLUSION: Musculo-skeletal pain is reported by 55-60 % of middle aged persons in Oslo during a four week period, and must be considered a normal phenomenon. Poor social conditions, inactivity, mental health problems and being an immigrant imply increased risk of more severe symptoms with a concomitant demand of health care.

Vitamin D deficiency and secondary hyperparathyroidism and the association with bone mineral density in persons with Pakistani and Norwegian background living in Oslo, Norway, The Oslo Health Study

We studied the prevalence of poor vitamin D status and the association with bone density in men and women born in Norway (quoted as Norwegians, n = 869) and Pakistan (quoted as Pakistanis, n = 177) in the population-based Oslo Health Study, 2000-2001. We measured 25-hydroxyvitamin D, iPTH and ionized calcium in serum and bone mineral density at the forearm site with single energy X-ray absorptiometry. Mean 25-hydroxyvitamin D was 74.8 +/- 23.7 nmol/l in the Norwegians and 25.0 +/- 13.6 nmol/l in the Pakistanis (P = 0.000). The prevalence of secondary hyperparathyroidism (iPTH > or = 8.5 pmol/l, 25-hydroxyvitamin D < 50 nmol/l and Ca2+ < or = 1.35 mmol/l) was four times higher in Pakistani compared to Norwegian women. Also in Pakistani men, serious vitamin D deficiency defined as secondary hyperparathyroidism was prevalent, and five times as frequent as in Norwegian men. However, whereas BMD was significantly lower in Norwegian women with, compared to Norwegian women without, secondary hyperparathyroidism, there was no difference in BMD between Pakistani women with and without secondary hyperparathyroidism. In conclusion, vitamin D deficiency was prevalent among Pakistani immigrants, and in great contrast to the vitamin D replete Norwegians. Serious vitamin D deficiency was interestingly not associated with reduced forearm bone density among Pakistani women.

Prevalence and predictors of vitamin D deficiency in five immigrant groups living in Oslo, Norway: the Oslo Immigrant Health Study

OBJECTIVE

To study the prevalence of vitamin D deficiency and to identify possible predictors of vitamin D deficiency in five main immigrant groups in Oslo.

DESIGN

Cross-sectional, population-based.

SETTING

City of Oslo.

SUBJECTS

In total, 491 men and 509 women with native countries Turkey, Sri Lanka, Iran, Pakistan and Vietnam living in the county of Oslo.

RESULTS

Median serum 25(OH)D level (s-25(OH)D) was 28 nmol/l, ranging from 21 nmol/l in women born in Pakistan to 40 nmol/l in men born in Vietnam. Overall prevalence of vitamin D deficiency defined as s-25(OH)D<25 nmol/l was 37.2%, ranging from 8.5% in men born in Vietnam to 64.9% in women born in Pakistan. s-25(OH)D did not vary significantly with age. s-25(OH)D was higher in blood samples drawn in June compared to samples obtained in April, but not significantly for women. Reported use of fatty fish and cod liver oil supplements showed a strong positive association with s-25(OH)D in all groups. Education length was positively associated with s-25(OH)D in women, whereas body mass index (BMI) was inversely associated with s-25(OH)D in women. These two variables were not related to vitamin D deficiency in men.

CONCLUSIONS

There is widespread vitamin D deficiency in both men and women born in Turkey, Sri Lanka, Iran, Pakistan and Vietnam residing in Oslo. The prevalence of vitamin D deficiency is higher in women than in men, and it is higher in those born in Pakistan and lower in those born in Vietnam compared to the other ethnic groups. Fatty fish intake and cod liver oil supplements are important determinant factors of vitamin D status in the groups studied. BMI and education length are also important predictors in women.