How many future dementia cases would be missed by a high-risk screening program? A retrospective cohort study in a population-based cohort.

INTRODUCTION: Risk prediction models aim to identify those at high risk to receive targeted interventions. We aimed to identify the proportion of future dementia cases that would be missed by a high-risk screening program. METHODS: We identified validated dementia risk prediction models from systematic reviews. We applied these to European Prospective Investigation of Cancer Norfolk, a large population-based cohort of 30,387 individuals with 29 years of linked healthcare data. RESULTS: A maximum of 16.0% (14.7,17.2) and 31.9% (30.2,33.5) of cases arose from the highest risk decile and quintiles, respectively. For every 1000 people considered to be at high risk, a maximum of 235 (215, 255) developed dementia. DISCUSSION: Seven in every 10 cases of dementia arose from people at normal risk, and eight in every 10 people at high risk did not develop dementia. Individual-level prevention approaches targeted at high-risk groups are unlikely to produce large reductions in disease incidence at the population level. HIGHLIGHTS: Dementia, a significant public health challenge, is not an inevitability of aging; risk reduction is possible. Several dementia risk prediction models have been validated in the general population, and these aim to identify people at high risk of the disease who can then be targeted with primary prevention interventions. An alternative prevention approach is to focus on interventions that reduce risk across the population, irrespective of risk status. In our study, seven out of every ten people who developed dementia during 29 year follow-up were classed as 'normal-risk' (rather than 'high risk') at baseline. Eight out of every ten people who were at high risk at baseline did not go on to develop dementia. Even if effective, dementia risk reduction efforts based upon targeted high-risk approaches are unlikely to reduce incidence of disease at the population level.

Changing patterns of health risk in adolescence: implications for health policy.

Adolescence is a time of physical, cognitive, social, and emotional development. This period is a very sensitive developmental window; environmental exposures, the development of health behaviours (eg, smoking and physical activity), and illness during adolescence can have implications for lifelong health. In the UK and other high-income countries, the experience of adolescence has changed profoundly over the past 20 years. Smoking, drug use, and alcohol consumption have all been in long-term decline. At the same time, obesity and mental ill health have increased and are now common among adolescents, with new risks (ie, vaping, psychoactive substances, and online harms) emerging. In this Viewpoint, we describe these and related trends in England and the UK. Although previous work has explored these changes in isolation, in this Viewpoint we consider them collectively. We explore what might be driving the changes and consider the implications for practice, policy, and research.

Estimated changes in free sugar consumption one year after the UK soft drinks industry levy came into force: controlled interrupted time series analysis of the National Diet and Nutrition Survey (2011-2019).

BACKGROUND: The UK soft drinks industry levy (SDIL) was announced in March 2016 and implemented in April 2018, encouraging manufacturers to reduce the sugar content of soft drinks. This is the first study to investigate changes in individual-level consumption of free sugars in relation to the SDIL. METHODS: We used controlled interrupted time series (2011-2019) to explore changes in the consumption of free sugars in the whole diet and from soft drinks alone 11 months after SDIL implementation in a nationally representative sample of adults (>18 years; n=7999) and children (1.5-19 years; n=7656) drawn from the UK National Diet and Nutrition Survey. Estimates were based on differences between observed data and a counterfactual scenario of no SDIL announcement/implementation. Models included protein consumption (control) and accounted for autocorrelation. RESULTS: Accounting for trends prior to the SDIL announcement, there were absolute reductions in the daily consumption of free sugars from the whole diet in children and adults of 4.8 g (95% CI 0.6 to 9.1) and 10.9 g (95% CI 7.8 to 13.9), respectively. Comparable reductions in free sugar consumption from drinks alone were 3.0 g (95% CI 0.1 to 5.8) and 5.2 g (95% CI 4.2 to 6.1). The percentage of total dietary energy from free sugars declined over the study period but was not significantly different from the counterfactual. CONCLUSION: The SDIL led to significant reductions in dietary free sugar consumption in children and adults. Energy from free sugar as a percentage of total energy did not change relative to the counterfactual, which could be due to simultaneous reductions in total energy intake associated with reductions in dietary free sugar.

The UK Soft Drinks Industry Levy and childhood hospital admissions for asthma in England.

Sugar sweetened beverage consumption has been suggested as a risk factor for childhood asthma symptoms. We examined whether the UK Soft Drinks Industry Levy (SDIL), announced in March 2016 and implemented in April 2018, was associated with changes in National Health Service hospital admission rates for asthma in children, 22 months post-implementation of SDIL. We conducted interrupted time series analyses (2012-2020) to measure changes in monthly incidence rates of hospital admissions. Sub-analysis was by age-group (5-9,10-14,15-18 years) and neighbourhood deprivation quintiles. Changes were relative to counterfactual scenarios where the SDIL wasn't announced, or implemented. Overall, incidence rates reduced by 20.9% (95%CI: 29.6-12.2). Reductions were similar across age-groups and deprivation quintiles. These findings give support to the idea that implementation of a UK tax intended to reduce childhood obesity may have contributed to a significant unexpected and additional public health benefit in the form of reduced hospital admissions for childhood asthma.

Changes in the number of new takeaway food outlets associated with adoption of management zones around schools: A natural experimental evaluation in England.

By the end of 2017, 35 local authorities (LAs) across England had adopted takeaway management zones (or "exclusion zones") around schools as a means to curb proliferation of new takeaways. In this nationwide, natural experimental study, we evaluated the impact of management zones on takeaway retail, including unintended displacement of takeaways to areas immediately beyond management zones, and impacts on chain fast-food outlets. We used uncontrolled interrupted time series analyses to estimate changes from up to six years pre- and post-adoption of takeaway management zones around schools. We evaluated three outcomes: mean number of new takeaways within management zones (and by three identified sub-types: full management, town centre exempt and time management zones); mean number on the periphery of management zones (i.e. within an additional 100 m of the edge of zones); and presence of new chain fast-food outlets within management zones. For 26 LAs, we observed an overall decrease in the number of new takeaways opening within management zones. Six years post-intervention, we observed 0.83 (95% CI -0.30, -1.03) fewer new outlets opening per LA than would have been expected in absence of the intervention, equivalent to an 81.0% (95% CI -29.1, -100) reduction in the number of new outlets. Cumulatively, 12 (54%) fewer new takeaways opened than would have been expected over the six-year post-intervention period. When stratified by policy type, effects were most prominent for full management zones and town centre exempt zones. Estimates of intervention effects on numbers of new takeaways on the periphery of management zones, and on the presence of new chain fast-food outlets within management zones, did not meet statistical significance. Our findings suggest that management zone policies were able to demonstrably curb the proliferation of new takeaways. Modelling studies are required to measure the possible population health impacts associated with this change.

Changes in the number and outcome of takeaway food outlet planning applications in response to adoption of management zones around schools in England: A time series analysis.

Physical exposure to takeaway food outlets ("takeaways") is associated with poor diet and excess weight, which are leading causes of excess morbidity and mortality. At the end of 2017, 35 local authorities (LAs) in England had adopted takeaway management zones (or "exclusion zones"), which is an urban planning intervention designed to reduce physical exposure to takeaways around schools. In this nationwide, natural experimental study, we used interrupted time series analyses to estimate the impact of this intervention on changes in the total number of takeaway planning applications received by LAs and the percentage rejected, at both first decision and after any appeal, within management zones, per quarter of calendar year. Changes in these proximal process measures would precede downstream retail and health impacts. We observed an overall decrease in the number of applications received by intervention LAs at 12 months post-intervention (6.3 fewer, 95% CI -0.1, -12.5), and an increase in the percentage of applications that were rejected at first (additional 18.8%, 95% CI 3.7, 33.9) and final (additional 19.6%, 95% CI 4.7, 34.6) decision, the latter taking into account any appeal outcomes. This effect size for the number of planning applications was maintained at 24 months, although it was not statistically significant. We also identified three distinct sub-types of management zone regulations (full, town centre exempt, and time management zones). The changes observed in rejections were most prominent for full management zones (where the regulations are applied irrespective of overlap with town centres), where the percentage of applications rejected was increased by an additional 46.1% at 24 months. Our findings suggest that takeaway management zone policies may have the potential to curb the proliferation of new takeaways near schools and subsequently impact on population health.

Population-level interventions for the primary prevention of dementia: a complex evidence review.

Dementia risk reduction is a global public health priority. Existing primary prevention approaches have favored individual-level interventions, with a research and policy gap for population-level interventions. We conducted a complex, multi-stage, evidence review to identify empirical evidence on population-level interventions for each of the modifiable risk factors identified by the Lancet Commission on dementia (2020). Through a comprehensive series of targeted searches, we identified 4604 articles, of which 135 met our inclusion criteria. We synthesized evidence from multiple sources, including existing non-communicable disease prevention frameworks, and graded the consistency and comprehensiveness of evidence. We derived a population-level intervention framework for dementia risk reduction, containing 26 high- and moderate-confidence policy recommendations, supported by relevant information on effect sizes, sources of evidence, contextual information, and implementation guidance. This review provides policymakers with the evidence they need, in a useable format, to address this critical public health policy gap. Funding: SW is funded by a National Institute for Health and Care Research (NIHR) Doctoral Fellowship. WW and LF are part funded by the NIHR Applied Research Collaboration East of England. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.

Impact of the UK soft drinks industry levy on health and health inequalities in children and adolescents in England: An interrupted time series analysis and population health modelling study.

BACKGROUND: The soft drinks industry levy (SDIL) in the United Kingdom has led to a significant reduction in household purchasing of sugar in drinks. In this study, we examined the potential medium- and long-term implications for health and health inequalities among children and adolescents in England. METHODS AND FINDINGS: We conducted a controlled interrupted time series analysis to measure the effects of the SDIL on the amount of sugar per household per week from soft drinks purchased, 19 months post implementation and by index of multiple deprivation (IMD) quintile in England. We modelled the effect of observed sugar reduction on body mass index (BMI), dental caries, and quality-adjusted life years (QALYs) in children and adolescents (0 to 17 years) by IMD quintile over the first 10 years following announcement (March 2016) and implementation (April 2018) of the SDIL. Using a lifetable model, we simulated the potential long-term impact of these changes on life expectancy for the current birth cohort and, using regression models with results from the IMD-specific lifetable models, we calculated the impact of the SDIL on the slope index of inequality (SII) in life expectancy. The SDIL was found to have reduced sugar from purchased drinks in England by 15 g/household/week (95% confidence interval: -10.3 to -19.7). The model predicts these reductions in sugar will lead to 3,600 (95% uncertainty interval: 946 to 6,330) fewer dental caries and 64,100 (54,400 to 73,400) fewer children and adolescents classified as overweight or obese, in the first 10 years after implementation. The changes in sugar purchasing and predicted impacts on health are largest for children and adolescents in the most deprived areas (Q1: 11,000 QALYs [8,370 to 14,100] and Q2: 7,760 QALYs [5,730 to 9,970]), while children and adolescents in less deprived areas will likely experience much smaller simulated effects (Q3: -1,830 QALYs [-3,260 to -501], Q4: 652 QALYs [-336 to 1,680], Q5: 1,860 QALYs [929 to 2,890]). If the simulated effects of the SDIL are sustained over the life course, it is predicted there will be a small but significant reduction in slope index of inequality: 0.76% (95% uncertainty interval: -0.9 to -0.62) for females and 0.94% (-1.1 to -0.76) for males. CONCLUSIONS: We predict that the SDIL will lead to medium-term reductions in dental caries and overweight/obesity, and long-term improvements in life expectancy, with the greatest benefits projected for children and adolescents from more deprived areas. This study provides evidence that the SDIL could narrow health inequalities for children and adolescents in England.

Estimated impact of the UK soft drinks industry levy on childhood hospital admissions for carious tooth extractions: interrupted time series analysis.

Introduction: Tooth extraction due to dental caries is associated with socioeconomic deprivation and is a major reason for elective childhood hospital admissions in England. Consumption of sugar-sweetened beverages is a risk factor for dental caries. We examined whether the soft drinks industry levy (SDIL), announced in March 2016 and implemented in April 2018, was associated with changes in incidence rates of hospital admissions for carious tooth extraction in children, 22 months post-SDIL implementation. Methods: Changes in incidence rates of monthly National Health Service hospital admissions for extraction of teeth due to a primary diagnosis of dental caries (International Classification of Diseases; ICD-10 code: K02) in England, between January 2012 and February 2020, were estimated using interrupted time series and compared with a counterfactual scenario where SDIL was not announced or implemented. Periodical changes in admissions, autocorrelation and population structure were accounted for. Estimates were calculated overall, by Index of Multiple Deprivation (IMD) fifths and by age group (0-4 years, 5-9 years, 10-14 years, 15-18 years). Results: Compared with the counterfactual scenario, there was a relative reduction of 12.1% (95% CI 17.0% to 7.2%) in hospital admissions for carious tooth extractions in all children (0-18 years). Children aged 0-4 years and 5-9 years had relative reductions of 28.6% (95% CI 35.6% to 21.5%) and 5.5% (95% CI 10.5% to 0.5%), respectively; no change was observed for older children. Reductions were observed in children living in most IMD areas regardless of deprivation. Conclusion: The UK SDIL was associated with reductions in incidence rates of childhood hospital admissions for carious tooth extractions, across most areas regardless of deprivation status and especially in younger children. Trial registration number: ISRCTN18042742.