Espen Bjertness

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

BackgroundResearch on health equity which mainly utilises population-based surveys, may be hampered by serious selection bias due to a considerable number of invitees declining to participate. Sufficient information from all the non-responders is rarely available to quantify this bias. Predictors of attendance, magnitude and direction of non-response bias in prevalence estimates and association measures, are investigated based on information from all 40 888 invitees to the Oslo Health Study.MethodsThe analyses were based on linkage between public registers in Statistics Norway and the Oslo Health Study, a population-based survey conducted in 2000/2001 inviting all citizens aged 30, 40, 45, 59–60 and 75–76 years. Attendance was 46%. Weighted analyses, logistic regression and sensitivity analyses are performed to evaluate possible selection bias.ResultsThe response rate was positively associated with age, educational attendance, total income, female gender, married, born in a Western county, living in the outer city residential regions and not receiving disability benefit. However, self-rated health, smoking, BMI and mental health (HCSL) in the attendees differed only slightly from estimated prevalence values in the target population when weighted by the inverse of the probability of attendance.Observed values differed only moderately provided that the non-attending individuals differed from those attending by no more than 50%. Even though persons receiving disability benefit had lower attendance, the associations between disability and education, residential region and marital status were found to be unbiased. The association between country of birth and disability benefit was somewhat more evident among attendees.ConclusionsSelf-selection according to sociodemographic variables had little impact on prevalence estimates. As indicated by disability benefit, unhealthy persons attended to a lesser degree than healthy individuals, but social inequality in health by different sociodemographic variables seemed unbiased. If anything we would expect an overestimation of the odds ratio of chronic disease among persons born in non-western countries.

The political origins of health inequity: prospects for change

Ole Petter Ottersen, Jashodhara Dasgupta, Chantal Blouin, Paulo Buss, Virasakdi Chongsuvivatwong, Julio Frenk, Sakiko Fukuda-Parr, Bience P Gawanas, Rita Giacaman, John Gyapong, Jennifer Leaning, Michael Marmot, Desmond McNeill, Gertrude I Mongella, Nkosana Moyo, Sigrun Møgedal, Ayanda Ntsaluba, Gorik Ooms, Espen Bjertness, Ann Louise Lie, Suerie Moon, Sidsel Roalkvam, Kristin I Sandberg, Inger B Scheel

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. DOI: http://dx.doi.org/10.7554/eLife.13410.001

Cohort Profile: Cohort of Norway (CONOR)

A number of large population-based cardiovascular surveys have been conducted in Norway since the beginning of the 1970s. The surveys were carried out by the National Health Screening Service in cooperation with the universities and local health authorities. All surveys comprised a common set of questions, standardized anthropometric and blood pressure measurements and non-fasting blood samples that were analysed for serum lipids at the Ulleval Hospital Laboratory. These surveys provided considerable experience in conducting large-scale population-based surveys, thus an important background for the Cohort of Norway (CONOR). In the late 1980s the Research Council of Norway established a programme in epidemiology. This also gave stimulus to the idea of establishing a cohort including both core survey data and stored blood samples. In the early 1990s, all universities, the National Health Screening Service, The National Institute of Public Health and the Cancer Registry discussed the possibility of a national representative cohort. The issue of storing blood samples for future analyses raised some concern and it was discussed in the parliament. In 1994, the Ministry of Health appointed the Steering Committee for the CONOR collaboration. In 1994–95, the fourth round of the Tromso Study was conducted, and became the first survey to provide data and blood samples for CONOR. During the years 1994–2003, a number of health surveys that were carried out in other counties and cities also provided similar data for the network. So far, 10 different surveys have provided data and blood samples for CONOR (Figure 1). The administrative responsibility for CONOR was given to the Norwegian Institute of Public Health (NIPH) in 2002. The CONOR collaboration is currently a research collaboration between the NIPH and the Universities of Bergen, Oslo, Tromso and Trondheim.

Indigenous and tribal peoples' health (The Lancet-Lowitja Institute Global Collaboration): a population study.

BACKGROUND International studies of the health of Indigenous and tribal peoples provide important public health insights. Reliable data are required for the development of policy and health services. Previous studies document poorer outcomes for Indigenous peoples compared with benchmark populations, but have been restricted in their coverage of countries or the range of health indicators. Our objective is to describe the health and social status of Indigenous and tribal peoples relative to benchmark populations from a sample of countries. METHODS Collaborators with expertise in Indigenous health data systems were identified for each country. Data were obtained for population, life expectancy at birth, infant mortality, low and high birthweight, maternal mortality, nutritional status, educational attainment, and economic status. Data sources consisted of governmental data, data from non-governmental organisations such as UNICEF, and other research. Absolute and relative differences were calculated. FINDINGS Our data (23 countries, 28 populations) provide evidence of poorer health and social outcomes for Indigenous peoples than for non-Indigenous populations. However, this is not uniformly the case, and the size of the rate difference varies. We document poorer outcomes for Indigenous populations for: life expectancy at birth for 16 of 18 populations with a difference greater than 1 year in 15 populations; infant mortality rate for 18 of 19 populations with a rate difference greater than one per 1000 livebirths in 16 populations; maternal mortality in ten populations; low birthweight with the rate difference greater than 2% in three populations; high birthweight with the rate difference greater than 2% in one population; child malnutrition for ten of 16 populations with a difference greater than 10% in five populations; child obesity for eight of 12 populations with a difference greater than 5% in four populations; adult obesity for seven of 13 populations with a difference greater than 10% in four populations; educational attainment for 26 of 27 populations with a difference greater than 1% in 24 populations; and economic status for 15 of 18 populations with a difference greater than 1% in 14 populations. INTERPRETATION We systematically collated data across a broader sample of countries and indicators than done in previous studies. Taking into account the UN Sustainable Development Goals, we recommend that national governments develop targeted policy responses to Indigenous health, improving access to health services, and Indigenous data within national surveillance systems. FUNDING The Lowitja Institute.

Consumption of Soft Drinks and Hyperactivity, Mental Distress, and Conduct Problems Among Adolescents in Oslo, Norway

OBJECTIVES We examined whether high levels of consumption of sugar-containing soft drinks were associated with mental distress, hyperactivity, and conduct problems among adolescents. METHODS A cross-sectional population-based survey was conducted with 10th-grade students in Oslo, Norway (n = 5498). We used the Hopkins Symptom Checklist and the Strengths and Difficulties Questionnaire to assess mental health outcomes. RESULTS There was a J-shaped dose-response relationship between soft drink consumption and mental distress, conduct problems, and total mental health difficulties score; that is, adolescents who did not consume soft drinks had higher scores (indicating worse symptoms) than those who consumed soft drinks at moderate levels but lower scores than those with high consumption levels. The relationship was linear for hyperactivity. In a logistic regression model, the association between soft drink consumption and mental health problems remained significant after adjustment for behavioral, social, and food-related variables. The highest adjusted odds ratios were observed for conduct problems among boys and girls who consumed 4 or more glasses of sugar-containing soft drinks per day. CONCLUSIONS High consumption levels of sugar-containing soft drinks were associated with mental health problems among adolescents even after adjustment for possible confounders.

Physicians who do not take sick leave: hazardous heroes?

Background: Physicians seem to have problems in accepting their own illness, and they tend to avoid taking sick leave. This study reports the diseases that physicians bring to work, and discusses selected factors associated with the behaviour of working when ill. Methods: Of a random sample of 1,476 Norwegian physicians, 70% answered a mailed, anonymous questionnaire as a part of The Norwegian Medical Associations health survey. Results: During one year, 80% of the physicians had worked during an illness for which they would have sick-listed their patients. More than half of the physicians in the study had worked whilst having an infectious disease. Factors independently associated with the behaviour of working when ill include being in the age group 30-39 years, working as a clinician outside hospital, having received medical treatment during the last three years, and having low job satisfaction . Conclusion : A large number of physicians work whilst having infections and other diseases. This behaviour might be harmful to the physicians themselves as well as to their patients and staff members.

Cardiovascular diseases, diabetes mellitus, and cancer in the occupied Palestinian territory

Heart disease, cerebrovascular disease, and cancer are the major causes of morbidity and mortality in the occupied Palestinian territory, resulting in a high direct cost of care, high indirect cost in loss of production, and much societal stress. The rates of the classic risk factors for atherosclerotic disease-namely, hypertension, diabetes mellitus, tobacco smoking, and dyslipidaemia-are high and similar to those in neighbouring countries. The urbanisation and continuing nutritional change from a healthy Mediterranean diet to an increasingly western-style diet is associated with reduced activity, obesity, and a loss of the protective effect of the traditional diet. Rates of cancer seem to be lower than those in neighbouring countries, with the leading causes of death being lung cancer in Palestinian men and breast cancer in women. The response of society and the health-care system to this epidemic is inadequate. A large proportion of health-care expenditure is on expensive curative care outside the area. Effective comprehensive prevention programmes should be implemented, and the health-care system should be redesigned to address these diseases.

Self-esteem and body satisfaction among late adolescents with acne: Results from a population survey

BACKGROUND The association of acne and self-evaluation is barely explored among late adolescents in the general population. OBJECTIVE We sought to explore self-esteem, body satisfaction, and acne among 18-year-old young adults at a community level. METHODS We conducted a questionnaire-based survey among 3775 late adolescents. RESULTS Our response rate was 80%. The prevalence of acne was 13.5%. Girls and boys with acne had significantly more depressive symptoms, lower self-attitude, more feelings of uselessness, fewer feelings of pride, lower self-worth, and lower body satisfaction than those without acne. In a regression model adjusting for body mass index and depressive symptoms, acne explained significantly poor self-attitude for boys only (odds ratio 2.07 [confidence interval 1.10; 3.88]) and poor self-worth for girls only (odds ratio 1.88 [confidence interval 1.23; 2.88]). LIMITATIONS Not all items of the self-esteem instrument were included. CONCLUSIONS At age 18 years, acne is related to self-evaluation independent of body mass index and depressive symptoms.

Neuropathological diagnoses in elderly patients in Oslo: Alzheimer's disease, lewy body disease, vascular lesions

Neuropathological changes in elderly residents of Oslo, Norway were characterised with respect to the cerebral substrates of dementia. Ninety-two brains were examined, representing 41% of all deaths occurring in 10 nursing homes during a 9-month period. The autopsy cohort showed a similar mean age (85 years) and sex ratio (73% female) and proportion of demented patients (75%) compared to all the patients resident in these homes who died during the same period. Clinical data was compiled retrospectively. Diagnosis was made using the CERAD protocol, and criteria for the diagnosis of Lewy body dementia. Lewy body formation was present in 20% and cerebral infarction in 21% of patients. In the demented group (69 patients) 90% fulfilled CERAD criteria for definite or probable Alzheimers disease. Eight demented cases had absent neocortical neurofibrillary tangles and 6 other cases showed Lewy body dementia (9% of demented patients). A further 8 of these demented cases had brain stem Lewy bodies with only minimal cortical involvement. Thirteen cases (19% of the sample) had cerebral infarcts but these were considered to be clinically significant in only 4 (6%). In the non-demented patients (23) 4 patients had brain stem Lewy bodies and 6 had cerebral infarcts. Despite inclusion criteria biased towards the collection of Alzheimers disease and normal patients, both Lewy body dementia (7%) and cerebral infarcts contributing to dementia (6%) were frequent.