How much of the stalled mortality trends in Scotland and England can be attributed to obesity?

OBJECTIVES: The rate of improvement in all-cause mortality rates has slowed in the UK since around 2012. While evidence suggests that UK Government 'austerity' policies have been largely responsible, it has been proposed that rising obesity may also have contributed. The aim here was to estimate this contribution for Scotland and England. METHODS: We calculated population attributable fractions (PAFs) resulting from changes in Body Mass Index (BMI) between the mid-1990s and late 2000s for all-cause mortality among 35-89-year olds in 2017-2019. We used BMI data from national surveys (the Scottish Health Survey and the Health Survey for England), and HRs from a meta-analysis of 89 European studies. PAFs were applied to mortality data for 2017-2019 (obtained from national registries), enabling comparison of observed rates, BMI-adjusted rates and projected rates. Uncertainty in the estimates is dominated by the assumptions used and biases in the underlying data, rather than random variation. A series of sensitivity analyses and bias assessments were therefore undertaken to understand the certainty of the estimates. RESULTS: In Scotland, an estimated 10% (males) and 14% (females) of the difference between observed and predicted mortality rates in 2017-2019 may be attributable to previous changes in BMI. The equivalent figures for England were notably higher: 20% and 35%, respectively. The assessments of bias suggest these are more likely to be overestimates than underestimates. CONCLUSIONS: Some of the recent stalled mortality trends in Scotland and England may be associated with earlier increases in obesity. Policies to reduce the obesogenic environment, including its structural and commercial determinants, and reverse the impacts of austerity, are needed.

Psychometric Validation of the Revised Family Affluence Scale: a Latent Variable Approach.

The aim was to develop and test a brief revised version of the family affluence scale. A total of 7120 students from Denmark, Greenland, Italy, Norway, Poland, Romania, Scotland and Slovakia reported on a list of 16 potential indicators of affluence. Responses were subject to item screening and test of dimensionality. Bifactor analysis revealed a strong general factor of affluence in all countries, but with additional specific factors in all countries. The specific factors mainly reflected overlapping item content. Item screening was conducted to eliminate items with low discrimination and local dependence, reducing the number of items from sixteen to six: Number of computers, number of cars, own bedroom, holidays abroad, dishwasher, and bathroom. The six-item version was estimated with Samejima's graded response model, and tested for differential item functioning by country. Three of the six items were invariant across countries, thus anchoring the scale to a common metric across countries. The six-item scale correlated with parental reported income groups in six out of eight countries. Findings support a revision to six items in the family affluence scale.

Changes in the association between health complaint frequency and medicine use among adolescents in Scotland between 1998 and 2010.

OBJECTIVE: Medicines have the potential to cause harm, particularly when adolescents do not follow recommendations for use. In addition, medicine use in adolescence has been shown to track into adulthood. There is therefore a strong rationale to monitor changes in adolescent medicine use over time and understand the mechanisms behind these changes METHODS: Data from the 1998, 2006 and 2010 Scotland Health Behaviour in School-aged Children Survey were modelled using multilevel logistic regression, modelling medicine use for: headache, stomachache, sleeping difficulties and nervousness, as well as a combined medicine use measure. Models adjusted for year and frequency of health complaints to measure trends in medicine use, and an interaction term to measure the relationship between medicine use and health complaint frequency. RESULTS: Medicine use reduced between 1998 and 2010. Hownever having the majority of the reduction was observed between 1998 and 2006 for all five outcomes. Adjustment for health complaint frequency only explained some of this reduction. When an interaction term was added between year and health complaint frequency this was significant for boys' medicine use, suggesting that health complaint frequency became a better predictor of medicine use with time. Medicine use for stomachache among girls increased over time, and this increase became more pronounced after adjustment for stomachache frequency. CONCLUSION: Changes in health complaint frequency were only partly associated with reductions in medicine use between 1998 and 2010. Further monitoring of medicine use is recommended, particularly the use of medicine for sleep difficulties, and for stomachache among girls.

National Income and Income Inequality, Family Affluence and Life Satisfaction Among 13 year Old Boys and Girls: A Multilevel Study in 35 Countries.

Adolescence is a critical period where many patterns of health and health behaviour are formed. The objective of this study was to investigate cross-national variation in the relationship between family affluence and adolescent life satisfaction, and the impact of national income and income inequality on this relationship. Data from the 2006 Health Behaviour in School-aged Children: WHO collaborative Study (N = 58,352 across 35 countries) were analysed using multilevel linear and logistic regression analyses for outcome measures life satisfaction score and binary high/low life satisfaction. National income and income inequality were associated with aggregated life satisfaction score and prevalence of high life satisfaction. Within-country socioeconomic inequalities in life satisfaction existed even after adjustment for family structure. This relationship was curvilinear and varied cross-nationally. Socioeconomic inequalities were greatest in poor countries and in countries with unequal income distribution. GDP (PPP US$) and Gini did not explain between country variance in socioeconomic inequalities in life satisfaction. The existence of, and variation in, within-country socioeconomic inequalities in adolescent life satisfaction highlights the importance of identifying and addressing mediating factors during this life stage.

Study design VII. Randomised controlled trials.

Previously in this series, I have given an overview of the main types of study design and the techniques used to minimise the likelihood of obtaining biased results. In this article I describe more fully randomised controlled trials, their uses, advantages and limitations.

Study design VI - Ecological studies.

Previously in this series I have given an overview of the main types of study design and the techniques used to minimise biased results. In this article I describe more fully ecological studies, their uses, advantages and limitations.

Study design V. Case-control studies.

Previously in this series I have given an overview of the main types of study design and the techniques used to minimise biased results. In this article I describe more fully case control studies, their uses, advantages and limitations.

Study design IV. Cohort studies.

Previously in this series I have given an overview of the main types of study design and the techniques used to minimise biased results. In this article I describe more fully cohort studies, their uses, advantages and limitations.

Study design III: Cross-sectional studies.

In this series, I previously gave an overview of the main types of study design and the techniques used to minimise biased results. Here, I describe cross-sectional studies, their uses, advantages and limitations.

Study design II. Issues of chance, bias, confounding and contamination.

In the first article in the series I explained the importance of study design and gave an overview of the main types of design. Here, I describe the ways in which the results of a study may deviate from the truth and the measures that can be taken to help minimise this when designing a study.

Study design I.

This is the first of a series of articles that will describe the different types of study design; considerations when choosing a study design; and the advantages and disadvantages of each type of study. This first article explains the importance of choosing an appropriate design and the decisions to be made when doing so.