Geographical variation in cardiovascular disease mortality in Norway: The role of life course socioeconomic position and parental health

Despite substantial geographical variation in cardiovascular (CVD) mortality within countries, little is known about whether this variation can be explained by individuals' life course socioeconomic position (SEP) or differences in family history of premature CVD deaths. Cox proportional hazards models were used to investigate the association between the county of residence at ages 50-59 and CVD death in Norwegians born between 1940 and 1959 and survived to at least age 60, using national data. Individual life course SEP and family history of premature CVD death reduced the geographical variation in CVD mortality across Norwegian counties, but some significant differences remained. Furthermore, CVD risk varied by residents' migration histories between two counties with distinct CVD and socioeconomic profiles.

Corrigendum: Understanding Adolescents' Perceptions of Diarrhea: A Formative Research Study of a Visual Scale to Measure Self-Reported Diarrhea in Low-Resource Settings

[This corrects the article DOI: 10.3389/fpubh.2021.561367.].

Understanding Adolescents' Perceptions of Diarrhea: A Formative Research Study of a Visual Scale to Measure Self-Reported Diarrhea in Low-Resource Settings

Introduction: Although water, sanitation, and hygiene interventions are effective in reducing diarrhea, there are methodological issues regarding the research tools used to evaluate their health impact. Moreover, there is limited research on individuals' subjective interpretations of diarrheal illness which may introduce further limitations in relying on self-reported data. Therefore, we conducted a study that aims to understand adolescents' perceptions of diarrheal illness in rural Tamil Nadu, India. Next, we wish to explore the acceptability of the Bristol Stool Form Scale to assess self-reported diarrhea in water, sanitation, and hygiene interventions involving adolescent participants in low-resource settings.

Materials and Methods: The study was conducted as part of the formative research phase in the cultural adaptation of Project SHINE, a school-based educational water, sanitation, and hygiene intervention in Thirumalaikodi, Tamil Nadu, India. A convergent parallel mixed-methods study design with a purposive sampling strategy was used. Qualitative data included 10 in-depth interviews with student participants aged 13–14. Quantitative data were collected through interviewer-administered face-to-face surveys (n = 14) and one-week stool diaries (n = 14). Each data set was analyzed separately and compiled during the interpretation of the findings.

Results: Across all data sets, diarrhea was reported to be perceived as unhealthy and an irregular occurrence among participants. Participants also reported diarrheal-taboos, local methods to cure or control diarrhea, and discussed how diarrheal illness can lead to absenteeism or withdrawal from school and social activities. Moreover, participants were able to understand and answer questions about their stool using the Bristol Stool Form Scale, suggesting that is an acceptable tool.

Discussion: Visual tools demonstrate promise in improving self-reported diarrheal illness among adolescents in low-resource settings in India. However, until we address diarrhea-related taboos it will be difficult to address methodological issues in the assessment and reporting of diarrheal illness among adolescents.

The role of occupational meaningfulness and citizenship as mediators between occupational status and recovery: a cross-sectional study among residents with co-occurring problems

Purpose

Engagement in meaningful occupations and being included as full citizens of the community, is essential in everyday life, and may be of considerable relevance for recovery and quality of life. However, persons with co-occurring substance use and mental health problems experience extensive obstacles to engagement in occupations and citizenship. The relationship between objective measures of occupational status and subjective experiences of occupational meaningfulness, citizenship and recovery, is scarcely researched in the context of co-occurring problems. As such, the purpose of this study is to examine associations between occupational status, occupational meaningfulness, citizenship and recovery and quality of life and to examine the roles of occupational meaningfulness and citizenship as possible mediators between occupational status and recovery and quality of life.

Design/methodology/approach

The study used a cross-sectional design with a sample of 104 residents at supported housing sites across six Norwegian cities.

Findings

Linear regression analyzes indicated that occupational status was significantly associated with the citizenship domains caring for others and community participation and with the quality of life measure positive affect. Occupational meaningfulness and citizenship were significantly associated with different domains of recovery and quality of life. Furthermore, mediation analyzes showed that the relationship between occupational status and recovery and quality of life was mediated by caring for others and community participation.

Originality/value

The results suggest that emphasizing opportunities for occupational meaningfulness and citizenship in practice may have positive implications for recovery among persons with co-occurring problems.

Time trends in HPV vaccination according to country background: a nationwide register-based study among girls in Norway

Background

Since the human papillomavirus (HPV) vaccine was introduced in Norway in 2009, the vaccine uptake has increased. Whether this increase is similar regardless of the girls’ country background is unknown. We examined changes in HPV vaccine uptake from 2009 to 2014 and studied the impact of parental education and income on HPV vaccine uptake according to country background.

Methods

Girls in the first six birth cohorts (1997–2002) eligible for HPV vaccination were identified through the National Registry. Information on HPV vaccination, country background and socioeconomic factors was extracted from the Norwegian Immunisation Registry and Statistics Norway. Risk differences (RDs) and confidence intervals (CIs) were estimated with linear binomial regression. A total of 177,387 girls were included in the study.

Results

The HPV vaccine uptake increased from 72.5% in 2009 to 87.3% in 2014. The uptake increased for girls in all country background categories. Highest vaccine uptake was observed in girls with East−/South-East Asian background, 88.9% versus 82.5% in the total population. Vaccine uptake decreased slightly with increasing parental education, RD = − 1.6% (95% CI: − 2.3% to − 0.8%) for highest compared with lowest education level. In contrast, the uptake increased with increasing household income, RD = 4.9% (95% CI, 4.3 to 5.5%) for highest compared with lowest quintile. Parental education had largest impact in girls with Asian background, RD = − 8.1% (95% CI − 10.5% to − 5.6%) for higher vs lower education. The largest impact of household income was observed in girls with background from Middle East/Africa, RD for a 200,000 NOK increase in income was 2.1% (95% CI 1.2 to 3.0%).

Conclusions

The HPV vaccine uptake differed with country background but increased over time in all country background categories. Moreover, the impact of education and income on vaccine uptake differed with country background.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10877-8.

Disentangling how the built environment relates to children's well-being: Participation in leisure activities as a mediating pathway among 8-year-olds based on the Norwegian Mother and Child Cohort Study

There is scarce insight into the role of the built environment for children's subjective well-being. In an attempt to increase our knowledge on this matter, we conducted a cross-sectional study comprising 23,043 children from the Norwegian Mother and Child Cohort Study. Information about children's leisure activities and their moods and feelings were linked to geospatial data on green space, facilities and population density to assess whether these built characteristics are related to subjective well-being and if participating in leisure activities is a mediator in such relations. We found that children having a park and more playgrounds/sports fields in the neighborhood, as well as those living in more densely populated areas, had more depressive moods and negative feelings. However, participating in leisure-time physical activity, organized activities and social activity with friends mediated these relations and contributed to counterbalancing some of the negative associations observed. The findings suggest that planners and policy makers should focus on ensuring children have neighborhood resources and venues that could support engagement in leisure activities that add positive experiences for their subjective well-being.

Ethnic differences in risk of hip fracture in Norway: a NOREPOS study

Hip fracture is a major public health problem, and the incidence rates vary considerably between countries. Ethnic differences in bone mineral density have been identified as a factor to explain some of the geographical differences in rates of hip fracture. In this Norwegian register-based study, we found that all immigrant groups experienced lower risk of hip fracture than individuals born in Norway.

INTRODUCTION

Norway is among the countries with the highest incidence rates. The aim of this study was to investigate differences in risk of hip fracture between ethnic groups living in Norway.

METHODS

We linked individuals in the Norwegian Population and Housing Census conducted in 2001 and a database consisting of all hip fractures in Norway in the period 2001-2013. Residents (n = 1,392,949) between 50 and 89 years and born in nine different geographical regions of the world were examined, and we computed age-standardized incidence rates for the different geographic regions-denoted ethnic groups in the paper. Gender-stratified Cox regression analysis, adjusted for age, was used to model risk of hip fracture as a function of region of birth.

RESULTS

Age-standardized incidence rates of hip fracture varied considerably between regions of birth living in Norway, in both genders. All immigrant groups had lower risk of hip fracture compared to the Norwegian-born population. Immigrants from Central and Southeast Asia had the lowest risk of hip fracture when compared to individuals born in Norway (HR = 0.2, 95% CI 0.1-0.3 and HR =0.2, 95% CI 0.2-0.4 in men and women, respectively).

CONCLUSION

Lower risk of hip fracture was found in all immigrant groups compared to the Norwegian-born majority population.

Recovery, quality of life and issues in supported housing among residents with co-occurring problems: a cross-sectional study

Purpose

Recovery for residents who experience co-occurring problems and live in supported housing takes place in everyday contexts. This study aims to explore residents’ self-reported recovery and quality of life and examine the relationships between these factors and issues in supported housing.

Design/methodology/approach

A cross-sectional study was conducted at 21 supported housing sites in six cities across Norway. A total of 104 residents (76 men and 28 women) responded to measures of recovery (Recovery Assessment Scale – Revised), life satisfaction (Manchester Short Assessment of Quality of Life), affect (single items), staff support (Brief INSPIRE) and sense of home (single items).

Findings

Linear regression analyses indicated associations between recovery and staff support (B = 0.01, 95% CI = 0.01-0.02, ß = 0.39), housing satisfaction (B = 0.15, 95% CI = 0.07-0.22, ß = 0.38), sense of home (B = 0.23, 95% CI = 0.14-0.32, ß = 0.49) and satisfaction with personal economy (B = 0.11, 95% CI = 0.05-0.17, ß = 0.33). Similarly, associations were found between life satisfaction and staff support (B = 0.03, 95% CI = 0.02-0.04, ß = 0.46), housing satisfaction (B = 0.63, 95% CI = 0.46-0.80, ß = 0.60), sense of home (B = 0.65, 95% CI = 0.42-0.87, ß = 0.51) and satisfaction with personal economy (B = 0.34, 95% CI = 0.19-0.50, ß = 0.39).

Originality/value

The findings imply that core issues in supported housing, namely, staff support, housing satisfaction, sense of home and satisfaction with personal economy, are associated with recovery and quality of life.

The effect of nitrogen dioxide on low birth weight in women with inflammatory bowel disease: a Norwegian pregnancy cohort study (MoBa)

Background: Adverse birth outcomes are more frequent among mothers with inflammatory bowel diseases (IBDs) than non-IBD mothers. In recent studies, air pollution, such as high concentrations of nitrogen dioxide (NO₂), is reckoned as a risk factor for preterm birth in the general population. In this study, we investigated whether IBD mothers are at higher risk of preterm birth when exposed to NO₂ compared to non-IBD mothers.Methods: We used information from the Norwegian Mother, Father and Child Cohort Study (MoBa). The pregnancy cohort was linked to the Norwegian Medical Birth Registry and air-pollution exposure data available from a subset of the study cohort. The relevant outcome in this study was preterm birth. A total of 16,170 non-IBD and 92 IBD mothers were included in the study.Results: The mean exposure of NO₂ during the pregnancy was similar for IBD and non-IBD mothers, 13.7 (6.9) μg/m³ and 13.6 (4.2) μg/m³, respectively.IBD mothers with higher exposure of NO₂ in the second and third trimester were at significant risk of preterm birth compared to non-IBD mothers [OR = 1.28 (CI 95%: 1.04-1.59) and OR = 1.23 (95% CI: 1.06-1.43), respectively]. The mean NO₂ exposure was significantly higher in IBD mothers with preterm birth than in IBD mothers who delivered at term, at 19.58 (1.57) μg/m³ and 12.89 (6.37) μg/m³, respectively.Conclusions: NO₂ exposure influenced the risk of preterm birth in IBD mothers. Higher risk of preterm birth in IBD was associated with higher exposure of NO₂, suggesting vulnerability of preterm birth in IBD when exposed to NO₂.

Intake of dairy protein during pregnancy in IBD and risk of SGA in a Norwegian population-based mother and child cohort

BACKGROUND

Patients with inflammatory bowel disease (IBD) tend to avoid dairy products to minimize abdominal pain and diarrhea. The aim of this study was to estimate the proportion of protein from dairy sources (PPDS) in mothers with and without IBD, and to explore the impact of PPDS on inadequate gestational weight gain (GWG) or small for gestational age (SGA) in IBD compared to non-IBD in the population-based Norwegian Mother, Father and Child Cohort Study (MoBa).

METHODS

MoBa includes about 95,000 pregnant women recruited throughout Norway from 1999 to 2008. IBD phenotype and complications during pregnancy and delivery were ascertained. This study included 148 mothers with Crohn disease (CD) and 194 with ulcerative colitis and 68,858 non-IBD mothers. In mid-pregnancy participants answered a comprehensive semi-quantitative food frequency questionnaire assessing diet since the start of pregnancy. PPDS was ranked in quartiles. The two lowest quartiles were merged and considered to represent the lowest of three PPDS groups. We used logistic regression analyses to model multivariate associations, adjusting for potential confounders.

RESULTS

The risk of belonging to the lowest PPDS group was twice as high in IBD mothers compared to non-IBD mothers (aOR = 2.02, 95% CI: 1.53, 2.67). Low compared to high PPDS strongly predicted inadequate GWG in CD (aOR = 4.22, 95% CI: 1.28, 13.92). Surprisingly, and in opposition to the non-IBD mothers, PPDS was positively associated with the risk of SGA in IBD mothers. IBD mother with low PPDS was associated with significantly lower risk of SGA than non-IBD mothers and IBD mothers with high PPDS (aOR = 0.19, 95% CI: 0.07, 0.50). The interaction term IBD/PPDS was the factor that linked SGA to IBD compared to non-IBD, and increased the association between IBD and SGA with a factor of three.

CONCLUSION

This study shows that intake of dairy products is lower in IBD mothers than in non-IBD mothers, and further, that low intake of dairy products in IBD mothers is associated with reduced risk of SGA compared to non-IBD and IBD mothers with high PPDS.

Neighborhood green spaces, facilities and population density as predictors of activity participation among 8-year-olds: a cross-sectional GIS study based on the Norwegian mother and child cohort study

BACKGROUND

A rapidly growing body of research suggests that qualities of the built environment can promote active living among children and youth. Nevertheless, shortcomings in the current evidence for understanding which built environment characteristics provide opportunities for taking part in activities in childhood remain. This study aimed to examine whether population density, green spaces, and facilities/amenities are associated with participation in leisure-time physical activity (PA), organized activities, and social activities with friends and peers in Norwegian 8-year-olds.

METHODS

Data from a sample of 23,043 children from the Norwegian Mother and Child Cohort Study (MoBa) were linked with geospatial data about the built environment. The questionnaire data reported by mothers provided information on the children's leisure activities. We computed exposure to neighborhood population density and access to green spaces and facilities/amenities within 800- and 5000-m radii of the participants' home addresses using geographic information systems. Associations were estimated using logistic regression models.

RESULTS

We found beneficial associations between having a park within 800-m and more leisure-time PA during the summer. Furthermore, children living in neighborhoods with higher proportions of green space participated in more PA during the winter. More densely populated areas and access to facilities were associated with participation in organized and social activities. Specifically, we observed that more playgrounds/sport fields in the neighborhood were the strongest and most consistent correlate of activity participation in Norwegian 8-year-olds by being related to more socialization with friends and peers.

CONCLUSION

This population-based study underscores the importance of access to a variety of venues and opportunities for different activities in the immediate neighborhood surroundings and in the greater community to support participation in physical activity and organized and social activities in childhood.

Preeclampsia and Hypertension During Pregnancy in Areas with Relatively Low Levels of Traffic Air Pollution

Objectives Air pollution exposure may contribute to the development of preeclampsia and hypertension during pregnancy. However, the evidence for such a relation is still limited. We investigated the associations between exposure for moderate to low levels of air pollution during pregnancy and preeclampsia and gestational hypertension in selected urban and county areas of Norway. Methods This study used a sub-group of 17,533 women in the Norwegian Mother and Child Cohort Study. Air pollution levels at residential addresses were estimated using land use regression models and back-extrapolated to the period of each pregnancy. Information on preeclampsia and gestational hypertension were obtained from the Medical Birth Registry of Norway and information on lifestyle factors was collected from questionnaires completed by the women during pregnancy. Results Moderate mean levels of NO₂ (13.6 ± 6.9 µg/m³) at residential address during pregnancy were not associated with preeclampsia and pregnancy hypertension. We found no statistically significant associations per 10 µg/m³ change in NO₂ exposure and preeclampsia (adjusted OR 0.89, 95% CI 0.74, 1.08) or hypertension during pregnancy (adjusted OR 0.91, 95% CI 0.78, 1.06). Conclusions for Practice In this large Norwegian pregnancy cohort, we found no statistically significant associations for moderate to low levels of pregnancy NO₂ exposure and preeclampsia or hypertension during pregnancy.

Particulate matter air pollution components and incidence of cancers of the stomach and the upper aerodigestive tract in the European Study of Cohorts of Air Pollution Effects (ESCAPE)

INTRODUCTION

Previous analysis from the large European multicentre ESCAPE study showed an association of ambient particulate matter <2.5 μm (PM_2.5) air pollution exposure at residence with the incidence of gastric cancer. It is unclear which components of PM are most relevant for gastric and also upper aerodigestive tract (UADT) cancer and some of them may not be strongly correlated with PM mass. We evaluated the association between long-term exposure to elemental components of PM_2.5 and PM₁₀ and gastric and UADT cancer incidence in European adults.

METHODS

Baseline addresses of individuals were geocoded and exposure was assessed by land-use regression models for copper (Cu), iron (Fe) and zinc (Zn) representing non-tailpipe traffic emissions; sulphur (S) indicating long-range transport; nickel (Ni) and vanadium (V) for mixed oil-burning and industry; silicon (Si) for crustal material and potassium (K) for biomass burning. Cox regression models with adjustment for potential confounders were used for cohort-specific analyses. Combined estimates were determined with random effects meta-analyses.

RESULTS

Ten cohorts in six countries contributed data on 227,044 individuals with an average follow-up of 14.9 years with 633 incident cases of gastric cancer and 763 of UADT cancer. The combined hazard ratio (HR) for an increase of 200 ng/m³ of PM_2.5_S was 1.92 (95%-confidence interval (95%-CI) 1.13;3.27) for gastric cancer, with no indication of heterogeneity between cohorts (I² = 0%), and 1.63 (95%-CI 0.88;3.01) for PM_2.5_Zn (I² = 70%). For the other elements in PM_2.5 and all elements in PM₁₀ including PM₁₀_S, non-significant HRs between 0.78 and 1.21 with mostly wide CIs were seen. No association was found between any of the elements and UADT cancer. The HR for PM_2.5_S and gastric cancer was robust to adjustment for additional factors, including diet, and restriction to study participants with stable addresses over follow-up resulted in slightly higher effect estimates with a decrease in precision. In a two-pollutant model, the effect estimate for total PM_2.5 decreased whereas that for PM_2.5_S was robust.

CONCLUSION

This large multicentre cohort study shows a robust association between gastric cancer and long-term exposure to PM_2.5_S but not PM₁₀_S, suggesting that S in PM_2.5 or correlated air pollutants may contribute to the risk of gastric cancer.

Air pollution and incidence of cancers of the stomach and the upper aerodigestive tract in the European Study of Cohorts for Air Pollution Effects (ESCAPE)

Air pollution has been classified as carcinogenic to humans. However, to date little is known about the relevance for cancers of the stomach and upper aerodigestive tract (UADT). We investigated the association of long-term exposure to ambient air pollution with incidence of gastric and UADT cancer in 11 European cohorts. Air pollution exposure was assigned by land-use regression models for particulate matter (PM) below 10 µm (PM10 ), below 2.5 µm (PM2.5 ), between 2.5 and 10 µm (PMcoarse ), PM2.5 absorbance and nitrogen oxides (NO2 and NOX ) as well as approximated by traffic indicators. Cox regression models with adjustment for potential confounders were used for cohort-specific analyses. Combined estimates were determined with random effects meta-analyses. During average follow-up of 14.1 years of 305,551 individuals, 744 incident cases of gastric cancer and 933 of UADT cancer occurred. The hazard ratio for an increase of 5 µg/m3 of PM2.5 was 1.38 (95% CI 0.99; 1.92) for gastric and 1.05 (95% CI 0.62; 1.77) for UADT cancers. No associations were found for any of the other exposures considered. Adjustment for additional confounders and restriction to study participants with stable addresses did not influence markedly the effect estimate for PM2.5 and gastric cancer. Higher estimated risks of gastric cancer associated with PM2.5 was found in men (HR 1.98 [1.30; 3.01]) as compared to women (HR 0.85 [0.5; 1.45]). This large multicentre cohort study shows an association between long-term exposure to PM2.5 and gastric cancer, but not UADT cancers, suggesting that air pollution may contribute to gastric cancer risk.

Is There an Association Between Ambient Air Pollution and Bladder Cancer Incidence? Analysis of 15 European Cohorts

BACKGROUND

Ambient air pollution contains low concentrations of carcinogens implicated in the etiology of urinary bladder cancer (BC). Little is known about whether exposure to air pollution influences BC in the general population.

OBJECTIVE

To evaluate the association between long-term exposure to ambient air pollution and BC incidence.

DESIGN, SETTING, AND PARTICIPANTS

We obtained data from 15 population-based cohorts enrolled between 1985 and 2005 in eight European countries (N=303431; mean follow-up 14.1 yr). We estimated exposure to nitrogen oxides (NO2 and NOx), particulate matter (PM) with diameter <10μm (PM10), <2.5μm (PM2.5), between 2.5 and 10μm (PM2.5-10), PM2.5absorbance (soot), elemental constituents of PM, organic carbon, and traffic density at baseline home addresses using standardized land-use regression models from the European Study of Cohorts for Air Pollution Effects project.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used Cox proportional-hazards models with adjustment for potential confounders for cohort-specific analyses and meta-analyses to estimate summary hazard ratios (HRs) for BC incidence.

RESULTS AND LIMITATIONS

During follow-up, 943 incident BC cases were diagnosed. In the meta-analysis, none of the exposures were associated with BC risk. The summary HRs associated with a 10-μg/m3 increase in NO2 and 5-μg/m3 increase in PM2.5 were 0.98 (95% confidence interval [CI] 0.89-1.08) and 0.86 (95% CI 0.63-1.18), respectively. Limitations include the lack of information about lifetime exposure.

CONCLUSIONS

There was no evidence of an association between exposure to outdoor air pollution levels at place of residence and risk of BC.

PATIENT SUMMARY

We assessed the link between outdoor air pollution at place of residence and bladder cancer using the largest study population to date and extensive assessment of exposure and comprehensive data on personal risk factors such as smoking. We found no association between the levels of outdoor air pollution at place of residence and bladder cancer risk.

Dietary Patterns in women with Inflammatory Bowel Disease and Risk of Adverse Pregnancy Outcomes: Results from The Norwegian Mother and Child Cohort Study (MoBa)

BACKGROUND

The aim of the study was to examine dietary patterns and risk of adverse pregnancy outcomes among mothers with inflammatory bowel disease (IBD) in the Norwegian Mother and Child Cohort Study (MoBa).

METHOD

MoBa enrolled participants from all over Norway between 1999 and 2008, and the study comprised 83,988 mothers, of whom there were 183 mothers with Crohn's disease (CD) and 240 with ulcerative colitis (UC). An additional questionnaire was submitted to mothers with IBD in 2013. We extracted three exploratory dietary patterns: a "Prudent," a "Western," and a "Traditional" pattern. We explored the relationship between dietary patterns and IBD and dietary patterns and adverse pregnancy outcomes: small for gestational age (SGA) and preterm delivery (PTD).

RESULTS

IBD mothers had a significantly lower adherence to the Traditional dietary pattern [mean score -0.10 (95% CI: - 0.2 - - 0.01)] than non-IBD mothers. In IBD mothers, middle and high adherence to the Traditional dietary pattern was associated with lower risk of SGA [OR tertile 2 vs. tertile 1: 0.44 (95% CI: 0.20 - 0.97) and OR tertile 3 vs. tertile 1: 0.23 (95% CI: 0.08-0.61)] than in IBD and non-IBD mothers with low adherence. In the IBD-subset analyses, similar results were demonstrated for UC mothers [OR tertile 2 vs. tertile 1: 0.21 (95% CI: 0.05 - 0.80) and OR tertile 3 vs. tertile 1: 0.16 (95% CI: 0.04 - 0.60)].

CONCLUSION

In IBD mothers, higher adherence to a Traditional dietary pattern, characterized by high consumption of lean fish, fish products, potatoes, rice porridge, cooked vegetables, and gravy, was associated with lower risk of SGA.

Pregnancy exposure to air pollution and early childhood respiratory health in the Norwegian Mother and Child Cohort Study (MoBa)

OBJECTIVES

It is unclear whether maternal air pollution exposure during pregnancy induces changes in the developing respiratory system of a child and whether it has consequences for respiratory health in early childhood. We investigated associations between exposure to moderate levels of air pollution during pregnancy and early childhood lower respiratory tract infections (LRTI) and wheezing.

METHODS

This study used a subgroup of 17 533 participants in the Norwegian Mother and Child Cohort Study. Air pollution levels at residential addresses were estimated using land use regression models, and back-extrapolated to the period of each pregnancy. Information on LRTI and wheezing and lifestyle factors was collected from questionnaires completed by mothers during pregnancy and when the child was 6 and 18 months of age.

RESULTS

Moderate mean levels of NO₂ (13.6 µg/m³, range 0.01-60.4) exposure at residential address during pregnancy were not statistically associated with LRTI and wheezing. No association was found per 10 µg/m³ change in NO₂ exposure and LRTI before the age of 6 months (adjusted risk ratio (RR) 0.99; 95% CI 0.84 to 1.17), or between 6 and 18 months of age (adjusted RR 1.05; 95% CI 0.94 to 1.16). Similarly, we found no association per 10 µg/m³ change in NO₂ exposure and wheezing between 6 and 18 months of age (adjusted RR 1.02; 95% CI 0.97 to 1.07).

CONCLUSIONS

There were no statistically significant associations for moderate levels of pregnancy NO₂ exposure and respiratory health outcomes during early childhood in overall analyses.

Long-Term Exposure to Ambient Air Pollution and Incidence of Postmenopausal Breast Cancer in 15 European Cohorts within the ESCAPE Project

BACKGROUND

Epidemiological evidence on the association between ambient air pollution and breast cancer risk is inconsistent.

OBJECTIVE

We examined the association between long-term exposure to ambient air pollution and incidence of postmenopausal breast cancer in European women.

METHODS

In 15 cohorts from nine European countries, individual estimates of air pollution levels at the residence were estimated by standardized land-use regression models developed within the European Study of Cohorts for Air Pollution Effects (ESCAPE) and Transport related Air Pollution and Health impacts – Integrated Methodologies for Assessing Particulate Matter (TRANSPHORM) projects: particulate matter (PM) ≤2.5μm, ≤10μm, and 2.5–10μm in diameter (PM2.5, PM10, and PMcoarse, respectively); PM2.5 absorbance; nitrogen oxides (NO2 and NOx); traffic intensity; and elemental composition of PM. We estimated cohort-specific associations between breast cancer and air pollutants using Cox regression models, adjusting for major lifestyle risk factors, and pooled cohort-specific estimates using random-effects meta-analyses.

RESULTS

Of 74,750 postmenopausal women included in the study, 3,612 developed breast cancer during 991,353 person-years of follow-up. We found positive and statistically insignificant associations between breast cancer and PM2.5 {hazard ratio (HR)=1.08 [95% confidence interval (CI): 0.77, 1.51] per 5 μg/m3}, PM10 [1.07 (95% CI: 0.89, 1.30) per 10 μg/m3], PMcoarse[1.20 (95% CI: 0.96, 1.49 per 5 μg/m3], and NO2 [1.02 (95% CI: 0.98, 1.07 per 10 μg/m3], and a statistically significant association with NOx [1.04 (95% CI: 1.00, 1.08) per 20 μg/m3, p=0.04].

CONCLUSIONS

We found suggestive evidence of an association between ambient air pollution and incidence of postmenopausal breast cancer in European women. https://doi.org/10.1289/EHP1742.

Association between urban green space and self-reported lifestyle-related disorders in Oslo, Norway

AIMS

The need for studies from more countries on the relationship between urban green space and health has been emphasized. The aim of this study was to investigate the association between two types of measurement of urban green space and self-reported lifestyle-related disorders in Oslo, Norway.

METHODS

Self-reported measures on mental disorders, asthma, type 2 diabetes and musculoskeletal pain of 8638 participants in the Oslo Health Study (HUBRO) were linked to two types of green space variables: the vegetation cover greenness derived from satellite data, which shows the city's vegetation cover regardless of property boundaries, and the land use greenness derived from municipal plans showing information about publicly accessible vegetation-covered areas. Associations between greenness and health measures were analysed by logistic regression models controlling for possible individual and contextual confounders.

RESULTS

Increasing vegetation cover greenness was associated with fewer self-reported mental disorders for both men and women after controlling for possible confounders. The proportion of women who reported high levels of musculoskeletal pain increased with increasing degrees of both of the greenness measurements, but no significant association was observed for men. No association was found for asthma and diabetes type 2 for either men or women.

CONCLUSIONS

Although there was a positive association between vegetation cover greenness and self-reported mental disorders, the main findings showed mixed results. The lack of clear associations between urban green space and lifestyle-related health disorders in Oslo might have been influenced by a large proportion of the inhabitants having easy access to green areas.

Long-term exposure to ambient air pollution and traffic noise and incident hypertension in seven cohorts of the European study of cohorts for air pollution effects (ESCAPE)

Aims

We investigated whether traffic-related air pollution and noise are associated with incident hypertension in European cohorts.

Methods and results

We included seven cohorts of the European study of cohorts for air pollution effects (ESCAPE). We modelled concentrations of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5), ≤10 µm (PM10), >2.5, and ≤10 µm (PMcoarse), soot (PM2.5 absorbance), and nitrogen oxides at the addresses of participants with land use regression. Residential exposure to traffic noise was modelled at the facade according to the EU Directive 2002/49/EC. We assessed hypertension as (i) self-reported and (ii) measured (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg or intake of BP lowering medication (BPLM). We used Poisson regression with robust variance estimation to analyse associations of traffic-related exposures with incidence of hypertension, controlling for relevant confounders, and combined the results from individual studies with random-effects meta-analysis. Among 41 072 participants free of self-reported hypertension at baseline, 6207 (15.1%) incident cases occurred within 5-9 years of follow-up. Incidence of self-reported hypertension was positively associated with PM2.5 (relative risk (RR) 1.22 [95%-confidence interval (CI):1.08; 1.37] per 5 µg/m³) and PM2.5 absorbance (RR 1.13 [95% CI:1.02; 1.24] per 10 - 5m - 1). These estimates decreased slightly upon adjustment for road traffic noise. Road traffic noise was weakly positively associated with the incidence of self-reported hypertension. Among 10 896 participants at risk, 3549 new cases of measured hypertension occurred. We found no clear associations with measured hypertension.

Conclusion

Long-term residential exposures to air pollution and noise are associated with increased incidence of self-reported hypertension.

Associations between green area in school neighbourhoods and overweight and obesity among Norwegian adolescents

The aim of the present study was to investigate the relationship between green areas and adolescents' body mass index (BMI). This is based on the notion that nature environment is known to have beneficial effects on human health, and that some of the explanation for this is that green areas are especially motivating or suitable as arenas for physical activity. We included 10,527 participants from the Norwegian Youth Study, which was conducted between 2001 and 2004. The participants reported body weight, height, and important potential confounding variables about lifestyle, family situation, and neighbourhood characteristics. Green area was assessed from land cover maps and we calculated the percentage of green areas within 1 km and 5 km buffers around the adolescents' schools. We found that the percentage of overweight and obese adolescents increased significantly when the percentage of green areas in the participants' surrounding increased (p < 0.001 for both outcomes and buffer sizes). The same results were found in logistic regression models where we adjusted for a large set of variables. As an example, the odds for being overweight was 1.38 times higher (95% CI: 1.02-1.85) for participants living in the most green surroundings compared to participants living in the least green surroundings (1 km buffer). Norwegian green areas are typically farmland, woods, and mountains, and we speculate if these areas are less accessible and attractive for adolescents, who might need more facilitated green areas for sport and physical activity.

Inadequate Gestational Weight Gain Predicts Adverse Pregnancy Outcomes in Mothers with Inflammatory Bowel Disease: Results from a Prospective US Pregnancy Cohort

BACKGROUND

Malnutrition and weight loss are common features of patients with inflammatory bowel disease (IBD).

AIM

To explore the impact of inadequate gestational weight gain (GWG) on adverse outcomes among IBD mothers in the prospective US pregnancy in Inflammatory Bowel Disease and Neonatal Outcomes (PIANO) cohort.

METHODS

The PIANO cohort comprises 559 and 363 pregnant mothers with Crohn's disease (CD) and ulcerative colitis (UC), respectively, enrolled between 2006 and 2014. The mothers were followed during and after pregnancy to ascertain medication, measurement of disease activity and complications during pregnancy and at delivery. Inadequate GWG was based on US Institute of Medicine recommendations. The associations between inadequate GWG and adverse pregnancy outcomes in maternal IBD were analyzed, adjusted for diabetes, hypertension, smoking, maternal age, education, and disease activity.

RESULTS

Maternal CD and UC with inadequate GWG had a 2.5-fold increased risk of preterm birth (OR 2.5, CI 1.3, 4.9 and OR 2.5, CI 1.2, 5.6). Furthermore, an increased risk of intrauterine growth restriction and a trend for small for gestational age were demonstrated in CD but not in UC (OR 3.3, CI 1.1, 10.0, OR 4.5, CI 0.8, 24.3, p = 0.08). Flares increased risk of inadequate GWG (OR 1.6, CI 1.2, 2.3, p = 0.002) but did not change the associations between inadequate GWG and adverse pregnancy outcomes in our models.

CONCLUSION

The US PIANO cohort demonstrated that inadequate GWG was a strong independent predictor of adverse pregnancy outcomes in IBD mothers.

Associations between long commutes and subjective health complaints among railway workers in Norway

Commuting is an important aspect of daily life for many employees, but there is little knowledge of how this affects individual commuters' health and well-being. The authors investigated the relationship between commuting and subjective health complaints, using data from a web-based questionnaire. In a sample of 2126 railway employees, 644 (30.3%) had long commute times. A 29-item inventory was used to measure the number and degree of the subjective health complaints. Those who commuted 60 min or more each way were characterized by significantly higher numbers and degrees of subjective health complaints compared with their peers with short commutes. The mean number of complaints was 7.5 among the former group and 6.4 for the latter group (p = 0.009). In a regression model, in which the authors controlled for age, gender, education, self-rated health, and coping, the employees with long commutes reported more complaints than those with short commutes. Significant associations were found between those with long commutes and the number and degree of incidences of self-reported musculoskeletal pain, pseudo-neurologic complaints, and gastrointestinal problems. Commuters who had had long commutes for more than 10 years reported more gastrointestinal and musculoskeletal complaints than those with long commutes for less than 2 years. Also, commuters with long commutes spent less time with their families and leisure activities compared with those with short commutes. The authors conclude that the association between long commute times and higher levels of subjective health complaints should attract the attention of transport planners, employers, and public health policymaker.

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Long commuters reported more subjective health symptoms than short commuters.

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Musculoskeletal, gastrointestinal and pseudo neurological complaints were most frequent.

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Long commuters spent less time with their families and on leisure activities than short commuters.

Association between pregnancy exposure to air pollution and birth weight in selected areas of Norway

BACKGROUND

Exposure to air pollution has adverse effects on cardiopulmonary health of adults. Exposure to air pollution in pregnancy may affect foetal development. However, the evidence of such effect remains inconsistent. We investigated the effects of exposure to air pollution during pregnancy on birth outcomes.

METHODS

This study, based within the Norwegian Mother and Child Cohort Study (MoBa), includes 17,533 participants living in the two largest cities in Norway: Oslo and Bergen, and their two surrounding counties: Akershus and Hordaland. Air pollution levels at residential addresses were estimated using land use regression models and back-extrapolated to the period of each pregnancy using continuous monitoring station data. Birth outcomes were birth weight, low birth weight, gestational age, and preterm delivery obtained from the Medical Birth Registry of Norway. Information on lifestyle factors was collected from MoBa questionnaires completed by mothers during pregnancy. Linear and logistic regression models were used to analyse the associations between pregnancy NO2 exposure and birth outcomes.

RESULTS

We found a statistically significant negative association between pregnancy exposure to NO2 and birth weight -43.6 (95%CI -55.8 to -31.5) g per 10 μg/m(3) NO2. However, after adjusting for either area or the combination of parity and maternal weight, no substantive effects of air pollution exposure were evident.

CONCLUSIONS

Exposure to air pollution during pregnancy was associated with decrease in birth weight, but area-related and lifestyle factors attenuated this association. We found no statistically significant associations of air pollution exposure with gestational age, low birth weight or preterm delivery.

Population data on calcium in drinking water and hip fracture: An association may depend on other minerals in water. A NOREPOS study

BACKGROUND

The Norwegian population has among the highest hip fracture rates in the world. The incidence varies geographically, also within Norway. Calcium in drinking water has been found to be beneficially associated with bone health in some studies, but not in all. In most previous studies, other minerals in water have not been taken into account. Trace minerals, for which drinking water can be an important source and even fulfill the daily nutritional requirement, could act as effect-modifiers in the association between calcium and hip fracture risk. The aim of the present study was to investigate the association between calcium in drinking water and hip fracture, and whether other water minerals modified this association.

MATERIALS AND METHODS

A survey of trace metals in 429 waterworks, supplying 64% of the population in Norway, was linked geographically to the home addresses of patients with incident hip fractures (1994-2000). Drinking water mineral concentrations were divided into "low" (below and equal waterworks average) and "high" (above waterworks average). Poisson regression models were fitted, and all incidence rate ratios (IRRs) were adjusted for age, geographic region, urbanization degree, type of water source, and pH of the water. Effect modifications were examined by stratification, and interactions between calcium and magnesium, copper, zinc, iron and manganese were tested both on the multiplicative and the additive scale. Analyses were stratified on gender.

RESULTS

Among those supplied from the 429 waterworks (2,110,916 person-years in men and 2,397,217 person-years in women), 5433 men and 13,493 women aged 50-85 years suffered a hip fracture during 1994-2000. Compared to low calcium in drinking water, a high level was associated with a 15% lower hip fracture risk in men (IRR=0.85, 95% CI: 0.78, 0.91) but no significant difference was found in women (IRR=0.98, 95%CI: 0.93-1.02). There was interaction between calcium and copper on hip fracture risk in men (p=0.051); the association between calcium and hip fracture risk was stronger when the copper concentration in water was high (IRR=0.52, 95% CI: 0.35, 0.78) as opposed to when it was low (IRR=0.88, 95% CI: 0.81, 0.94). This pattern persisted also after including potential confounding factors and other minerals in the model. No similar variation in risk was found in women.

CONCLUSION

In this large, prospective population study covering two thirds of the Norwegian population and comprising 19,000 hip fractures, we found an inverse association between calcium in drinking water and hip fracture risk in men. The association was stronger when the copper concentration in the water was high.

Co-occurrence of IBS and symptoms of anxiety or depression, among Norwegian twins, is influenced by both heredity and intrauterine growth

Background

Environmental and genetic factors contribute to variation in irritable bowel syndrome (IBS), anxiety and depression. Comorbidity between these disorders is high. A previous investigation of our population-based twin cohort revealed that low birth weight increased the risk for development of IBS, with environmental influences in utero as the most relevant contributing factor. We hypothesise that both intrauterine and genetic factors influence the co-occurrence of IBS and symptoms of anxiety and depression.

Methods

A postal questionnaire sent to 12700 Norwegian twins born between 1967 and 1979 comprised a checklist of 31 illnesses and symptoms, including IBS and symptoms of anxiety and depression. The influence of genetic factors and intrauterine growth on comorbidity between these disorders were analysed in the full sample and compared to those based on only monozygotic (MZ) twin pairs discordant for IBS (95 pairs) in birth weight group < 2500 g and ≥ 2500 g.

Results

In the co-twin analyses restricted growth (birth weight < 2500 g) was significantly associated with anxiety and depression (average birth weight difference of 181.0 g (p <0.0001) and 249.9 g (p < 0.0001), respectively).

The analysis of the full sample revealed that IBS was significantly associated with symptoms of anxiety (adjusted OR = 2.5, 95% CI: 1.9, 3.3) and depression (adjusted OR = 2.3. 95% CI: 1.8, 3.0). Analyses of MZ pairs discordant for IBS indicated significant associations between IBS and symptoms of anxiety (OR = 3.7, 95% CI: 1.3, 10.5) and between IBS and symptoms of depression (OR = 4.2, 95% CI: 1.7, 9.9) only in the birth weight group below 2500 g.

Conclusion

Our findings suggest that genetic factors partly explain the association between IBS and symptoms of anxiety and depression. In the low range of birth weight (<2500 g), restricted fetal growth seems to be a common contributing factor to the co-occurrence between these disorders.

Long-term exposure to air pollution and cardiovascular mortality: an analysis of 22 European cohorts

BACKGROUND

Air pollution has been associated with cardiovascular mortality, but it remains unclear as to whether specific pollutants are related to specific cardiovascular causes of death. Within the multicenter European Study of Cohorts for Air Pollution Effects (ESCAPE), we investigated the associations of long-term exposure to several air pollutants with all cardiovascular disease (CVD) mortality, as well as with specific cardiovascular causes of death.

METHODS

Data from 22 European cohort studies were used. Using a standardized protocol, study area-specific air pollution exposure at the residential address was characterized as annual average concentrations of the following: nitrogen oxides (NO2 and NOx); particles with diameters of less than 2.5 μm (PM2.5), less than 10 μm (PM10), and 10 μm to 2.5 μm (PMcoarse); PM2.5 absorbance estimated by land-use regression models; and traffic indicators. We applied cohort-specific Cox proportional hazards models using a standardized protocol. Random-effects meta-analysis was used to obtain pooled effect estimates.

RESULTS

The total study population consisted of 367,383 participants, with 9994 deaths from CVD (including 4,992 from ischemic heart disease, 2264 from myocardial infarction, and 2484 from cerebrovascular disease). All hazard ratios were approximately 1.0, except for particle mass and cerebrovascular disease mortality; for PM2.5, the hazard ratio was 1.21 (95% confidence interval = 0.87-1.69) per 5 μg/m and for PM10, 1.22 (0.91-1.63) per 10 μg/m.

CONCLUSION

In a joint analysis of data from 22 European cohorts, most hazard ratios for the association of air pollutants with mortality from overall CVD and with specific CVDs were approximately 1.0, with the exception of particulate mass and cerebrovascular disease mortality for which there was suggestive evidence for an association.

Road traffic noise, sleep and mental health

This study examines the relationship between road traffic noise, self-reported sleep quality and mental health. The study is cross-sectional and based on data from a survey conducted in Oslo, Norway, in 2000. Psychological distress (Hopkins Symptom Checklist, HSCL-25) was measured along with self-reported somatic health, sleep quality, noise sensitivity and socioeconomic variables. Questionnaire data were combined with modeled estimates of noise exposure. The total study sample consisted of 2898 respondents. After adjustment for potential confounders and stratifying for sleep quality, we found a positive, but not statistically significant association between noise exposure and symptoms of psychological distress among participants with poor sleep quality (slope=0.06, 95% CI: -0.02 to 0.13, per 10 dB increase in noise exposure). In the same sleep quality group, we found a borderline statistically significant association between noise exposure and a symptom level indicating a probable mental disorder (HSCL≥1.55) (odds ratio=1.47, 95% CI: 0.99-1.98, per 10 dB increase in noise exposure). We found no association between road traffic noise and mental health among subjects reporting good and medium sleep quality. The results suggest that road traffic noise may be associated with poorer mental health among subjects with poor sleep. Individuals with poor sleep quality may be more vulnerable to effects of road traffic noise on mental health than individuals with better sleep quality.

Long-term exposure to elemental constituents of particulate matter and cardiovascular mortality in 19 European cohorts: results from the ESCAPE and TRANSPHORM projects

BACKGROUND

Associations between long-term exposure to ambient particulate matter (PM) and cardiovascular (CVD) mortality have been widely recognized. However, health effects of long-term exposure to constituents of PM on total CVD mortality have been explored in a single study only.

AIMS

The aim of this study was to examine the association of PM composition with cardiovascular mortality.

METHODS

We used data from 19 European ongoing cohorts within the framework of the ESCAPE (European Study of Cohorts for Air Pollution Effects) and TRANSPHORM (Transport related Air Pollution and Health impacts--Integrated Methodologies for Assessing Particulate Matter) projects. Residential annual average exposure to elemental constituents within particle matter smaller than 2.5 and 10 μm (PM2.5 and PM10) was estimated using Land Use Regression models. Eight elements representing major sources were selected a priori (copper, iron, potassium, nickel, sulfur, silicon, vanadium and zinc). Cohort-specific analyses were conducted using Cox proportional hazards models with a standardized protocol. Random-effects meta-analysis was used to calculate combined effect estimates.

RESULTS

The total population consisted of 322,291 participants, with 9545 CVD deaths. We found no statistically significant associations between any of the elemental constituents in PM2.5 or PM10 and CVD mortality in the pooled analysis. Most of the hazard ratios (HRs) were close to unity, e.g. for PM10 Fe the combined HR was 0.96 (0.84-1.09). Elevated combined HRs were found for PM2.5 Si (1.17, 95% CI: 0.93-1.47), and S in PM2.5 (1.08, 95% CI: 0.95-1.22) and PM10 (1.09, 95% CI: 0.90-1.32).

CONCLUSION

In a joint analysis of 19 European cohorts, we found no statistically significant association between long-term exposure to 8 elemental constituents of particles and total cardiovascular mortality.

Do cadmium, lead, and aluminum in drinking water increase the risk of hip fractures? A NOREPOS study

The aim of this study was to investigate relations between cadmium, lead, and aluminum in municipality drinking water and the incidence of hip fractures in the Norwegian population. A trace metals survey in 566 waterworks was linked geographically to hip fractures from hospitals throughout the country (1994-2000). In all those supplied from these waterworks, 5,438 men and 13,629 women aged 50-85 years suffered a hip fracture. Poisson regression models were fitted, adjusting for age, region of residence, urbanization, and type of water source as well as other possibly bone-related water quality factors. Effect modification by background variables and interactions between water quality factors were examined (correcting for false discovery rate). Men exposed to a relatively high concentration of cadmium (IRR = 1.10; 95 % CI 1.01, 1.20) had an increased risk of fracture. The association between relatively high lead and hip fracture risk was significant in the oldest age group (66-85 years) for both men (IRR = 1.11; 95 % CI 1.02, 1.21) and women (IRR = 1.10; 95 % CI 1.04, 1.16). Effect modification by degree of urbanization on hip fracture risk in men was also found for all three metals: cadmium, lead, and aluminum. In summary, a relatively high concentration of cadmium, lead, and aluminum measured in drinking water increased the risk of hip fractures, but the associations depended on gender, age, and urbanization degree. This study could help in elucidating the complex effects on bone health by risk factors found in the environment.

Nationwide data on municipal drinking water and hip fracture: could calcium and magnesium be protective? A NOREPOS study

Norway has a high incidence of hip fractures, and the incidence varies by degree of urbanization. This variation may reflect a difference in underlying environmental factors, perhaps variations in the concentration of calcium and magnesium in municipal drinking water. A trace metal survey (1986-1991) in 556 waterworks (supplying 64% of the Norwegian population) was linked geographically to hip fractures from hospitals throughout the country (1994-2000). In all, 5472 men and 13,604 women aged 50-85years suffered a hip fracture. Poisson regression models were fitted, adjusting for age, urbanization degree, region of residence, type of water source, and pH. The concentrations of calcium and magnesium in drinking water were generally low. An inverse association was found between concentration of magnesium and risk of hip fracture in both genders (IRR men highest vs. lowest tertile=0.80, 95% CI: 0.74, 0.87; IRR women highest vs. lowest tertile=0.90, 95% CI: 0.85, 0.95), but no consistent association between calcium and hip fracture risk was observed. The highest tertile of urbanization degree (city), compared to the lowest (rural), was related to a 23 and 24% increase in hip fracture risk in men and women, respectively. The association between magnesium and hip fracture did not explain the variation in hip fracture risk between city and rural areas. Magnesium in drinking water may have a protective role against hip fractures; however this association should be further investigated.

Can temperature explain the latitudinal gradient of ulcerative colitis? Cohort of Norway

Background

Incidence and prevalence of ulcerative colitis follow a north–south (latitudinal) gradient and increases northwards at the northern hemisphere or southwards at the southern hemisphere. The disease has increased during the last decades. The temporal trend has been explained by the hygiene hypothesis, but few parallel explanations exist for the spatial variability. Many factors are linked to latitude such as climate. Our purpose was to investigate the association between variables governing the climate and prospectively identified patients.

Methods

In this study, we used a subset of the population-based Cohort of Norway (n = 80412) where 370 prevalent cases of ulcerative colitis were identified through self-reported medication. The meteorological and climatic variables temperature, precipitation, and altitude were recorded from weather stations of the Norwegian Meteorological Institute. Summer temperature was used to capture environmental temperature.

Results

Summer temperature was significantly related to the prevalence of ulcerative colitis. For each one-degree increase in temperature the odds for ulcerative colitis decreased with about 9% (95% CI: 3%-15%). None of the other climatic factors were significantly associated to the risk of ulcerative colitis. Contextual variables did not change the association to the prevalence of ulcerative colitis.

Conclusions

The present results show that the prevalence of ulcerative colitis is associated to summer temperature. Our speculation is that summer temperature works as an instrumental variable for the effect of microbial species richness on the development of ulcerative colitis. Environmental temperature is one of the main forces governing microbial species richness and the microbial composition of the commensal gut flora is known to be an important part in the process leading to ulcerative colitis.

Is the quality of drinking water a risk factor for self-reported forearm fractures? Cohort of Norway

SUMMARY

Compared to pH ≥7.0 in Norwegian municipal drinking water, pH <7.0 increased the risk of forearm fractures in the population-based Cohort of Norway (CONOR; n = 127,272). The association was attenuated (p > 0.05) after adjustments for indicators of bacteria and organic matter, which may signify an association between poor drinking water and bone health.

INTRODUCTION

The Norwegian population has the highest rate of fractures ever reported. A large variation in fracture rate both between and within countries indicates that an environmental factor, such as the quality of drinking water, could be one of the causes of the disparities. Our aim was to investigate a possible association between pH (an important parameter for water quality) and self-reported forearm fracture and to examine whether other water quality factors could account for this association.

METHODS

Using Geographic Information Systems, information on the quality of drinking water was linked to CONOR (n = 127,272; mean age, 50.2 ± 15.8 years), a database comprising ten regional epidemiological health surveys from across the country in the time period 1994-2003.

RESULTS

The highest risk of forearm fracture was found at a pH of around 6.75, with a decreasing risk toward both higher and lower pH values. The increased adjusted odds of forearm fracture in men consuming municipal drinking water with pH <7.0 compared to water with pH ≥7.0 was odds ratio (OR) = 1.19 (95 % CI, 1.14, 1.25), and the corresponding increased odds in women was OR = 1.14 (95 % CI, 1.08, 1.19). This association was attenuated (p > 0.05) after further adjustments for other water quality factors (color grade, intestinal enterococci, and Clostridium perfringens).

CONCLUSIONS

Our findings indicate a higher risk of fracture when consuming water of an acidic pH; however, the risk does not only seem to be due to the acidity level per se, but also to other aspects of water quality associated with pH.

[Overweight children--how important is the urban/rural factor?]

BACKGROUND

Targeted measures to prevent overweight children are dependent on a knowledge of which environmental factors play a part. We wanted to investigate whether overweight in Norwegian eight-year-olds is related to whether they live in urban or rural areas.

MATERIAL AND METHOD

In the cross-sectional study "Children's growth in Norway 2008", the weight, height and waist of 3473 eight-year-olds were measured. We examined relationships between overweight and waist measurement and centrality, population density and number of inhabitants in the municipalities where the children lived by means of regression analyses.

RESULT

In adjusted analyses, the odds on children in central municipalities being overweight was 34 lower than for children in less central municipalities (OR = 0.66; 95 % CI: 0.46-0.94), and children in municipalities with a high population density had on average 0.66 cm smaller waists than children in municipalities with a low population density (95 % CI: 0.02-1.31). The relationships between overweight and the explanatory variables population density and number of inhabitants, and between waist measurement and the explanatory variables centrality and population density showed the same tendency, but were not statistically significant in the adjusted analyses.

INTERPRETATION

The results indicate that there is a higher percentage of overweight children in rural areas than in urban areas. Education and income level in the municipalities appeared to explain some of the effect of the urbanity variables on overweight and waist measurement.

Ethnic differences in risk factors and total risk of cardiovascular disease based on the Norwegian CONOR study

BACKGROUND

Risk of cardiovascular disease varies between ethnic groups and the aim of this study was to investigate differences in cardiovascular risk factors, and total cardiovascular risk between ethnic groups in Norway.

DESIGN

Cross-sectional study using data from the Cohort of Norway (CONOR).

METHODS

A sample of 62,145 participants, 40-65 years of age, originating from 11 geographical regions, were included in our study. Self-reported variables, blood samples and physical measurements were used to estimate age- and time-adjusted mean values of cardiovascular risk factors for different ethnic groups. The 10-year risks of cardiovascular mortality and cardiovascular events were calculated using the Framingham and NORRISK risk models.

RESULTS

We observed differences between ethnic groups for cardiovascular risk factors and both Framingham and NORRISK risk scores. NORRISK showed significant differences by ethnicity in women only. Immigrants from the Indian subcontinent had the lowest high-density lipoprotein (HDL) levels, the highest levels of blood glucose, triglycerides, total cholesterol/HDL ratio, waist hip ratio and diabetes prevalence. Immigrants from the former Yugoslavia had the highest Framingham scores, high blood pressure, high total cholesterol/HDL ratio, overweight measures and smoking. Low cardiovascular risk was observed among East Asian immigrants.

CONCLUSION

The previously reported excess cardiovascular risk among immigrants from the Indian subcontinent was supported in this study. We also showed that immigrants from the former Yugoslavian countries had a higher total 10-year risk of cardiovascular events than other ethnic groups. This study adds information about ethnic groups in Norway which needs to be addressed in further research and targeted prevention strategies.

Inflammatory bowel disease in patients with primary sclerosing cholangitis: clinical characterization in liver transplanted and nontransplanted patients

BACKGROUND

Inflammatory bowel disease (IBD) in patients with primary sclerosing cholangitis (PSC) seems to differ from IBD without PSC, but a systematic, prospective study of IBD in PSC has until now not been reported. We aimed to describe the clinical, endoscopic, and histopathologic features of PSC-IBD in liver-transplanted and nontransplanted patients.

METHODS

PSC patients (n = 184) were included and underwent ileocolonoscopy with assessment of segmental histopathology.

RESULTS

A total of 155 (84%) patients had IBD, of whom 39 (25%) had undergone colectomy. The patients with an intact colon and complete tissue samples (n = 110) were further investigated. Forty-two (38%) patients had undergone liver transplantation. The median IBD duration was 11 (range, 0-50) years. The majority (65%) had no or sparse IBD symptoms. Inflammatory findings were more frequent by histology than by endoscopy (89% versus 47%, P < 0.001). Histopathological signs of inflammation involved the right colon in 86% of patients and were purely right-sided in 23%. The findings of inflammation were higher in the right compared to the left colon (P < 0.001), but the general inflammatory activity was low. Backwash ileitis was demonstrated in 20% (17/87) of patients and rectal sparing in 65% (70/107). The liver-transplanted patients had lower clinical (P = 0.035) and histological (P = 0.013) IBD activity than the nontransplanted group.

CONCLUSIONS

PSC-IBD may represent a distinct entity of colitis in which low endoscopic activity may mask an active histologic inflammation that possibly contributes to an increased risk of malignancy. Circumstances related to liver transplantation seem to act favorably on colonic inflammation in PSC.

Concordance for IBD among twins compared to ordinary siblings--a Norwegian population-based study

AIMS

Comparing the risk to develop concordant disease among twins with inflammatory bowel disease (IBD) to ordinary siblings. Moreover, clinical characteristics of IBD and the association between perinatal factors and IBD, were evaluated.

METHODS

Patients with IBD, enrolled from an incidence study between 1990 and 1994, and the twins were identified from the Norwegian national birth registry, which was established in 1967.

RESULTS

Eight monozygotic and 16 dizygotic pairs, in which at least one twin reported a positive history of IBD were compared to 84 patients with Crohn's disease (CD) and 87 patients with ulcerative colitis (UC) from the incidence study. The relative risks for concordant disease in monozygotic pairs were estimated to 95.4 (95% CI: 76.3, 114.6) and 49.5 (95% CI: 35.7, 63.3) for CD and UC, respectively. The corresponding risks in dizygotic pairs were 42.4 (95% CI: 29.6, 55.2) and 0.0. Among ordinary siblings of CD and UC the risks for concordance were 22.7 (95% CI: 13.3, 32.1) and 4.6 (95% CI: 0.4, 8.7), respectively. Stricturing disease was significantly higher in twins with CD compared to incidental cases. The first-born twin in pairs discordant for disease, 12 out of 19 (63.2%), tended to be affected by IBD (p=0.10).

CONCLUSION

Genetic factors influence the development of IBD and fibrostenotic disease in CD. The increased risk for concordant disease among dizygotic twins compared to ordinary siblings, at least in CD, might underscore the importance of shared environment in utero or in childhood.

Relationships between inflammatory bowel disease and perinatal factors: both maternal and paternal disease are related to preterm birth of offspring

BACKGROUND

The aims of this study were to explore the influences of familial, maternal, and paternal inflammatory disease (IBD) on perinatal outcomes in the offspring and the risk for development of IBD related to perinatal factors.

METHODS

Eighty-five patients with Crohn's disease (CD) and 86 with ulcerative colitis (UC) were included from a population-based incidence study enrolled 1990-1994. Family and birth records of these patients, as well as of their 207 infants, were drawn from the Norwegian Medical Birth Registry, established in 1967, and compared with the national birth cohort from the same period.

RESULTS

Maternal (odds ratio [OR] = 2.15, 95% confidence interval [CI]: 1.36, 3.39) and paternal IBD (OR = 3.02, 95% CI: 1.82, 5.01) influenced the risk of preterm birth (<37 weeks), which further increased if the affected parents had a first-degree relative with IBD (OR = 4.29, 95% CI: 1.59, 11.63). Maternal CD was associated with lower birth weight in the offspring (crude difference: 271.79 g, 95% CI: 87.83, 455.77, versus controls). Maternal UC increased the risk of perinatal bacterial infection in the offspring (OR = 6.03, 95% CI: 2.03, 17.91). IBD patients (2.3%) were less likely to be delivered by cesarean section than controls (8.1%) (OR = 0.27, CI: 95%: 0.10, 0.73).

CONCLUSIONS

Familial, maternal, and paternal IBD were linked to preterm birth, which might be explained by genetic mechanisms. The present protective effect of cesarean sections needs further clarification in future studies.

Widespread but not localized neoplasia in inflammatory bowel disease worsens the prognosis of colorectal cancer

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal cancer (CRC). Recently, new phenotypes of CRC in IBD have been suggested. Studies of the prognosis of CRC in IBD have shown conflicting results. The aim of the study was to analyze factors for prognosis in CRC-IBD, including the impact of the new phenotypes.

METHODS

By using the nationwide, population-based Cancer Registry of Norway, we compared survival of a CRC-IBD cohort with CRC in the background population (all-CRC), adjusting for the topographical distribution of dysplasia at cancer diagnosis (widespread versus localized neoplasia in IBD) and other factors. We also analyzed prognostic factors within CRC-IBD.

RESULTS

The mean age at CRC diagnosis was 43 years in widespread, 52 years in localized neoplasia IBD, and 70 years in all-CRC (P < 0.05). Adjusted for cofactors, prognosis of CRC-IBD was poorer compared to all-CRC (mortality rate ratio [MRR] 3.71, 95% confidence interval [CI]: 2.54-5.42, P < 0.001). Prognosis of widespread neoplasia IBD was poorer compared to all-CRC (MRR 4.27, 95% CI: 2.83-6.44, P < 0.001) and compared to localized neoplasia IBD (MRR 3.58, 95% CI: 0.87-14.72, P = 0.076). Survival was not significantly different between localized neoplasia IBD and all-CRC (P = 0.132).

CONCLUSIONS

The results demonstrate lower age and poorer survival of CRC in IBD compared to CRC in the background population. The unfavorable effect of IBD on prognosis of CRC was pronounced in widespread neoplasia IBD. The diagnosis of this phenotype seems to be an important prognostic sign in patients with CRC in IBD.

Clustering in time of familial IBD separates ulcerative colitis from Crohn's disease

BACKGROUND

The aim was to compare clustering of time at diagnosis and phenotype of inflammatory bowel disease (IBD) between affected parents and children and to explore generational differences in age at diagnosis (AAD) as well as the concordance of clinical characteristics.

METHODS

Eighty-four affected pairs from 45 families were included from 5 counties in southeastern Norway between August 2003 and December 2006; 43 were sib-sib pairs and 39 parent-child pairs. Clinical data were obtained by phone interviews and by hospital records.

RESULTS

The difference in median AAD was 17.0 years (P < 0.001) and 2.0 years (P = 0.29) in parent-child and sib-sib pairs, respectively. When the time interval between diagnosis in parent and child was split into 2 groups, below and above 5 years, 64% of pairs with ulcerative colitis (UC) offspring were diagnosed within 5 years, compared to 24% of pairs with Crohn's disease (CD) offspring (odds ratio [OR] = 5.7, 95% confidence interval [CI]: 1.4, 23.8). Concordance for smoking habits was low in 26 pairs with mixed disease (κ = 0.15), whereas patients with CD tended to be current smokers.

CONCLUSIONS

Most of the children acquire their disease at an earlier time in life compared to their parents, suggesting genetic anticipation. The time interval between diagnosis of the parents and offspring was lower when the offspring developed UC compared to CD, which might reflect the influence of shared environment on the generational difference in AAD in UC families. This study confirmed the effect of smoking habits on IBD phenotype.