Ragnhild Hovengen

WHO European Childhood Obesity Surveillance Initiative 2008: weight, height and body mass index in 6-9-year-old children.

What is already known about this subject Overweight and obesity prevalence estimates among children based on International Obesity Task Force definitions are substantially lower than estimates based on World Health Organization definitions. Presence of a north–south gradient with the highest level of overweight found in southern European countries. Intercountry comparisons of overweight and obesity in primary‐school children in Europe based on measured data lack a similar data collection protocol.

WHO European Childhood Obesity Surveillance Initiative: body mass index and level of overweight among 6–9-year-old children from school year 2007/2008 to school year 2009/2010

BackgroundThe World Health Organization (WHO) Regional Office for Europe has established the Childhood Obesity Surveillance Initiative (COSI) to monitor changes in overweight in primary-school children. The aims of this paper are to present the anthropometric results of COSI Round 2 (2009/2010) and to explore changes in body mass index (BMI) and overweight among children within and across nine countries from school years 2007/2008 to 2009/2010.MethodsUsing cross-sectional nationally representative samples of 6−9-year-olds, BMI, anthropometric Z-scores and overweight prevalence were derived from measured weight and height. Significant changes between rounds were assessed using variance and t-tests analyses.ResultsAt Round 2, the prevalence of overweight (including obesity; WHO definitions) ranged from 18% to 57% among boys and from 18% to 50% among girls; 6 − 31% of boys and 5 − 21% of girls were obese. Southern European countries had the highest overweight prevalence. Between rounds, the absolute change in mean BMI (range: from −0.4 to +0.3) and BMI-for-age Z-scores (range: from −0.21 to +0.14) varied statistically significantly across countries. The highest significant decrease in BMI-for-age Z-scores was found in countries with higher absolute BMI values and the highest significant increase in countries with lower BMI values. The highest significant decrease in overweight prevalence was observed in Italy, Portugal and Slovenia and the highest significant increase in Latvia and Norway.ConclusionsChanges in BMI and prevalence of overweight over a two-year period varied significantly among European countries. It may be that countries with higher prevalence of overweight in COSI Round 1 have implemented interventions to try to remedy this situation.

Social differences in smoking and snuff use among Norwegian adolescents: A population based survey

BackgroundA change in pattern of tobacco use has been observed in the last decade in Norway. Snuff use and occasional smoking have to some degree replaced daily smoking among adolescents and young adults. Daily smoking is known to be negatively associated with social background factors, but little is known about these associations for other types of tobacco use. Our aim was to study different types of tobacco use among adolescents according to gender, educational ambitions, family background factors, and urbanization.MethodsCross-sectional, school-based study with 15 931 participants and response-rate 87%, conducted among 15 and 16 year olds during 2000–2004.ResultsMore girls (33.8%) than boys (26.4%) were daily or occasional smokers, while more boys (21.4%) than girls (3.5%) were daily or occasional snuff users. Daily smoking was more common among adolescents planning vocational education, with single parents or poor family economy. Occasional smoking and snuff use (daily or occasionally) showed a similar, but less pronounced pattern regarding education and single parent families. Adolescents with parents from foreign countries were less likely to use tobacco. One exception was boys with parents from Muslim majority countries who had an increased risk of daily smoking. A typical combination user of both tobacco types was a Norwegian boy with divorced parents and ambitions to complete vocational studies or only one year of upper secondary school.ConclusionTobacco use in adolescents is mainly associated with low educational ambitions and less affluent self-reported family economy. Adolescents with divorced parents use more tobacco than those living with both parents. Public health initiatives to avoid or reduce tobacco use should mainly target adolescents in vocational studies and those leaving school early.

Important periods of weight development in childhood: a population-based longitudinal study

BackgroundIdentifying important ages for the development of overweight is essential for optimizing preventive efforts. The purpose of the study was to explore early growth characteristics in children who become overweight or obese at the age of 8 years to identify important ages for the onset of overweight and obesity.MethodsData from the Norwegian Child Growth Study in 2010 (N = 3172) were linked with repeated measurements from health records beginning at birth. Weight and height were used to derive the body mass index (BMI) in kg/m2. The BMI standard deviation score (SDS) for each participant was estimated at specific target ages, using a piecewise linear mixed effect model.ResultsAt 8 years of age, 20.4% of the children were overweight or obese. Already at birth, overweight children had a significantly higher mean BMI SDS than normal weight 8-year-olds (p < .001) and this difference increased in consecutive age groups in infancy and childhood. A relatively large increase in BMI during the first 9 months was identified as important for being overweight at 8 years. BMI SDS at birth was associated with overweight at 8 years of age (OR, 1.8; 1.6–2.0), and with obesity (OR, 1.8; 1.4–2.3). The Odds Ratios for the BMI SDS and change in BMI SDS further increased up to 1 year of age became very high from 2 years of age onwards.ConclusionsA high birth weight and an increasing BMI SDS during the first 9 months and high BMI from 2 years of age proved important landmarks for the onset of being overweight at 8 years of age. The risks of being overweight at 8 years appear to start very early. Interventions to prevent children becoming overweight should not only start at a very early age but also include the prenatal stage.

Adiposity among children in Norway by urbanity and maternal education: a nationally representative study

BackgroundInternational research has demonstrated that rural residency is a risk factor for childhood adiposity. The main aim of this study was to investigate the urban-rural gradient in overweight and obesity and whether the association differed by maternal education.MethodsHeight, weight and waist circumference (WC) were measured in a nationally representative sample of 3166 Norwegian eight-year-olds in 2010. Anthropometric measures were stratified by area of residence (urbanity) and maternal education. Risk estimates for overweight (including obesity) and waist-to-height ratio ≥0.5 were calculated by log-binomial regression.ResultsMean BMI and WC and risk estimates of overweight (including obesity) and waist-to-height ratio ≥0.5 were associated with both urbanity and maternal education. These associations were robust after mutual adjustment for each other. Furthermore, there was an indication of interaction between urbanity and maternal education, as trends of mean BMI and WC increased from urban to rural residence among children of low-educated mothers (p = 0.01 for both BMI and WC), whereas corresponding trends for children from higher educational background were non-significant (p > 0.30). However, formal tests of the interaction term urbanity by maternal education were non-significant (p-value for interaction was 0.29 for BMI and 0.31 for WC).ConclusionsIn this nationally representative study, children living rurally and children of low-educated mothers had higher mean BMI and waist circumference than children living in more urban areas and children of higher educated mothers.

WHO European Childhood Obesity Surveillance Initiative: School Nutrition Environment and Body Mass Index in Primary Schools

Background: Schools are important settings for the promotion of a healthy diet and sufficient physical activity and thus overweight prevention. Objective: To assess differences in school nutrition environment and body mass index (BMI) in primary schools between and within 12 European countries. Methods: Data from the World Health Organization (WHO) European Childhood Obesity Surveillance Initiative (COSI) were used (1831 and 2045 schools in 2007/2008 and 2009/2010, respectively). School personnel provided information on 18 school environmental characteristics on nutrition and physical activity. A school nutrition environment score was calculated using five nutrition-related characteristics whereby higher scores correspond to higher support for a healthy school nutrition environment. Trained field workers measured children’s weight and height; BMI-for-age (BMI/A) Z-scores were computed using the 2007 WHO growth reference and, for each school, the mean of the children’s BMI/A Z-scores was calculated. Results: Large between-country differences were found in the availability of food items on the premises (e.g., fresh fruit could be obtained in 12%−95% of schools) and school nutrition environment scores (range: 0.30−0.93). Low-score countries (Bulgaria, Czech Republic, Greece, Hungary, Latvia and Lithuania) graded less than three characteristics as supportive. High-score (≥0.70) countries were Ireland, Malta, Norway, Portugal, Slovenia and Sweden. The combined absence of cold drinks containing sugar, sweet snacks and salted snacks were more observed in high-score countries than in low-score countries. Largest within-country school nutrition environment scores were found in Bulgaria, Czech Republic, Greece, Hungary, Latvia and Lithuania. All country-level BMI/A Z-scores were positive (range: 0.20−1.02), indicating higher BMI values than the 2007 WHO growth reference. With the exception of Norway and Sweden, a country-specific association between the school nutrition environment score and the school BMI/A Z-score was not observed. Conclusions: Some European countries have implemented more school policies that are supportive to a healthy nutrition environment than others. However, most countries with low school nutrition environment scores also host schools with supportive school environment policies, suggesting that a uniform school policy to tackle the “unhealthy” school nutrition environment has not been implemented at the same level throughout a country and may underline the need for harmonized school policies.

Parental marital status and childhood overweight and obesity in Norway: a nationally representative cross-sectional study

Objective Sociodemographic changes in Norway and other western industrialised countries, including family structure and an increasing proportion of cohabiting and divorced parents, might affect the prevalence of childhood overweight and obesity issues. We aimed to examine whether parental marital status was associated with general and abdominal obesity among children. We also sought to explore whether the associations differed by gender. Design Cross-sectional. Setting 127 primary schools across Norway. Participant 3166 third graders (mean age 8.3 years) participating in the nationally representative Norwegian Child Growth Study in 2010. Measurements Height, weight and waist circumference were objectively measured. The main outcome measures were general overweight (including obesity; body mass index ≥25 kg/m2) using International Obesity Task Force (IOTF) cut-offs and abdominal obesity (waist-to-height ratio ≥0.5) by gender and parental marital status. Prevalence ratios, adjusted for possible confounders, were calculated by log-binomial regression. Results General overweight (including obesity) was 1.54 (95% CI 1.21 to 1.95) times more prevalent among children of divorced parents compared with children of married parents, and the corresponding prevalence ratio for abdominal obesity was 1.89 (95% CI 1.35 to 2.65). Formal tests of the interaction term parental marital status by gender were not statistically significant. However, in gender-specific analyses the association between parental marital status and adiposity measures was only statistically significant in boys (p=0.04 for general overweight (including obesity) and p=0.01 for abdominal obesity). The estimates were robust against adjustment for maternal education, family country background and current area of residence. Conclusions General and abdominal obesities were more prevalent among children of divorced parents. This study provides valuable information by focusing on societal changes in order to identify vulnerable groups.

Impact of instrument error on the estimated prevalence of overweight and obesity in population-based surveys

BackgroundThe basis for this study is the fact that instrument error increases the variance of the distribution of body mass index (BMI). Combined with a defined cut-off value this may impact upon the estimated proportion of overweight and obesity. It is important to ensure high quality surveillance data in order to follow trends of estimated prevalence of overweight and obesity. The purpose of the study was to assess the impact of instrument error, due to uncalibrated scales and stadiometers, on prevalence estimates of overweight and obesity.MethodsAnthropometric measurements from a nationally representative sample were used; the Norwegian Child Growth study (NCG) of 3474 children. Each of the 127 participating schools received a reference weight and a reference length to determine the correction value. Correction value corresponds to instrument error and is the difference between the true value and the measured, uncorrected weight and height at local scales and stadiometers. Simulations were used to determine the expected implications of instrument errors. To systematically investigate this, the coefficient of variation (CV) of instrument error was used in the simulations and was increased successively.ResultsSimulations showed that the estimated prevalence of overweight and obesity increased systematically with the size of instrument error when the mean instrument error was zero. The estimated prevalence was 16.4% with no instrument error and was, on average, overestimated by 0.5 percentage points based on observed variance of instrument error from the NCG-study. Further, the estimated prevalence was 16.7% with 1% CV of instrument error, and increased to 17.8%, 19.5% and 21.6% with 2%, 3% and 4% CV of instrument error, respectively.ConclusionsFailure to calibrate measuring instruments is likely to lead to overestimation of the prevalence of overweight and obesity in population-based surveys.

Childhood abuse and later worries about the baby's health in pregnancy

Objective. To explore the associations between sexual and/or physical abuse in childhood and worries about the babys health in pregnancy. Design. Cross‐sectional questionnaire study. Setting. Norwegian prospective pregnancy cohort. Sample. An original sample of 58,139 pregnancies (1999–2006) covering about 43% of the pregnant population. Methods. Two self‐reported questionnaires in the 17th and 30th week of gestation were merged with data from the Medical Birth Registry of Norway. Associations between physical and/or sexual childhood abuse and worries about the babys health were assessed with multiple logistic regression analyses. Main outcome measures. Strong worries about the babys health in the 30th week of gestation among women with experience of childhood abuse. Results. Women who reported being exposed to physical or sexual childhood abuse or a combination of the two were at increased risk of strong worries about the babys health compared to women who had not been similarly exposed (adjusted odds ratio (OR) = 1.62, 95% confidence interval (CI) 1.26–2.08; adjusted OR = 1.30, 95% CI 1.03–1.64; adjusted OR = 2.10, 95% CI 1.68–2.62, respectively). Marital status, adult abuse, pelvic pain, quality of antenatal care, self‐efficacy and previous birth experiences were also associated with concern about the babys health. Conclusions. There were significant associations between physical and/or sexual childhood abuse and strong concern about the babys health. Worries about the babys health are complex and associated with many elements of risk.

WHO European Childhood Obesity Surveillance Initiative: Impact of Type of Clothing Worn during Anthropometric Measurements and Timing of the Survey on Weight and Body Mass Index Outcome Measures in 6–9-Year-Old Children

Background. The World Health Organization European Childhood Obesity Surveillance Initiative (COSI) conducted examinations in 6–9-year-old children from 16 countries in the first two rounds of data collection. Allowing participating countries to adhere to their local legal requirements or adapt to other circumstances required developing a flexible protocol for anthropometric procedures. Objectives. (1) Review intercountry variation in types of clothing worn by children during weight and height measurements, clothes weight adjustments applied, timing of the survey, and duration of data collection; (2) assess the impact of the observed variation in these practices on the children’s weight or body mass index (BMI) outcome measures. Results. The relative difference between countries’ unadjusted and clothes-adjusted prevalence estimates for overweight was 0.3–11.5%; this figure was 1.4–33.3% for BMI-for-age Z-score values. Monthly fluctuations in mean BMI-for-age Z-score values did not show a systematic seasonal effect. The majority of the monthly BMI-for-age Z-score values did not differ statistically within a country; only 1–3 monthly values were statistically different within some countries. Conclusions. The findings of the present study suggest that the built-in flexibility in the COSI protocol concerning the data collection practices addressed in the paper can be kept and thus do not necessitate a revision of the COSI protocol.