Local food availability, diet and obesity: Development and empirical testing of a complex theory

Individuals with poor quality diets face an increased risk of developing a range of chronic diseases. Aspects of the local food environment, including food availability, have been linked to less healthy diets and increased body weight in adults. However, there is limited theory development to guide the synthesis of empirical studies or the design and evaluation of intervention strategies. Therefore, this dissertation sought to 1) develop a theory of change for unpacking the association between local food availability, diet quality and weight status through identifying hypothesized pathways of influence; and 2) test identified mechanisms using nationally representative data for adults across the United Kingdom and England. Firstly, a systematic review and realist synthesis were used to generate a novel theory of change for food availability, diet and obesity. This involved integration of tacit knowledge from an expert panel with evidence from a range of published food availability interventions. The resulting theory suggested that the influence of food availability on diet and weight status involves a complex set of pathways. Including the importance of understanding the link between the adoption of, and exposure to, different types of food outlets and the alignment of these factors with the preferences and needs of people of varying socioeconomic position (SEP). Thus, use of different away-from-home food outlets (i.e. fast food, restaurant and café) were examined in adults from the National Diet and Nutrition Survey showing that only use of fast food outlets (but not restaurants or cafés) was associated with poor diet quality and obesity, after accounting for SEP. Next, given the potential importance of exposure to the density of food outlets in their use, the same types of away-from-home food outlets were examined in a cross-sectional spatial study of adults from the first wave of the UK Household Longitudinal Study (UKHLS). This analysis showed that again, regardless of individual SEP, the density of fast food outlets around the home was positively associated with away-from-home food spending and obesity, while the density of restaurants was negatively associated with obesity and no link to the density of cafés. Lastly, preliminary longitudinal analysis using adults from five waves of the UKHLS explored the utility of residential relocation as a means of examining the effect of a change in exposure to away-from-home food outlet density on diet and obesity. Results suggest that relocation can lead to substantial change in food outlet exposures; however, relocation is also accompanied by changes in a variety of demographic and socioeconomic circumstances. Collectively, this work demonstrates that theory development and empirical testing can provide a solid conceptual foundation to improve our understanding of how food availability influences unhealthy diet and obesity, for different groups of people and across a range of circumstances. The application of this systematic approach could lead to a more nuanced view of mechanisms of action and thereby more effectively address complex public health problems.Cambridge International Scholarship, a scheme funded by the Cambridge Commonwealth, European & International Trust

Changes in consumption of added sugars from age 13 to 30 years: a systematic review and meta-analysis of longitudinal studies

Added sugar intake during adolescence has been associated with weight gain and cardiometabolic risk factors. Moreover, dietary habits may persist into adulthood, increasing chronic disease risk in later life. This systematic review investigated changes in intake of added sugars between the ages of 13 and 30 years. Literature databases were searched for longitudinal studies of diet during adolescence or early adulthood. Retrieved articles were screened for studies including multiple measures of intake of sugars or sugary foods from cohort participants between the ages of 13 and 30. Data were analysed using random-effects meta-analysis, by the three main nutrient and food group categories identified (PROSPERO: CRD42015030126). Twenty-four papers reported longitudinal data on intake of added sugar or sucrose ($n$ = 6), sugar-sweetened beverages (SSBs) ($n$ = 20) and/or confectionery ($n$ = 9). Meta-analysis showed a non-significant per year of age decrease in added sugar or sucrose intake (-0.15% total energy intake (95%CI -0.41; 0.12)), a decrease in confectionery consumption (-0.20 servings/week (95%CI -0.41; -0.001)) and a non-significant decrease in SSB consumption (-0.15 servings/week (95%CI -0.32; 0.02)). Taken together, the overall decrease in added sugar intake observed from adolescence to early adulthood may suggest opportunities for intervention to further improve dietary choices within this age range

Utilization of Away-From-Home Food Establishments, Dietary Approaches to Stop Hypertension Diet Pattern, and Obesity

$\textbf{Introduction:}$ Eating meals away from home has been associated with the consumption of unhealthy foods and increased body weight. However, more rigorous assessment of the contribution of different types of away-from-home food establishments to overall diet quality and obesity is minimal. This study examined usage of these food establishments, accordance to the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and obesity status in a nationally representative sample of adults in the United Kingdom. $\textbf{Methods:}$ A cross-sectional analysis of data from a national survey (N=2,083 aged ≥19 years, from 2008 to 2012) with dietary intake measured using a 4-day food diary, and height and weight measured objectively. Exposures included usage of (i.e., by proportion of energy) all away-from-home food establishments combined, and fast-food outlets, restaurants, and cafés separately. Outcomes included accordance with the DASH diet, and obesity status. Multivariable logistic regressions were conducted in 2016 to estimate associations between food establishments, diet quality, and obesity. $\textbf{Results:}$ People consuming a higher proportion of energy from any away-from-home food establishment had lower odds of DASH accordance (OR=0.45, 95% CI=0.31, 0.67) and increased odds of obesity (OR=1.48, 95% CI=1.10, 1.99). After adjustment, only use of fast-food outlets was significantly associated with lower odds of DASH accordance (OR=0.48, 95%=0.33, 0.69) and higher odds of obesity (OR=1.30, 95% CI=1.01, 1.69). $\textbf{Conclusions:}$ Although a greater reliance on eating away-from-home is associated with less-healthy diets and obesity, dietary public health interventions that target these food establishments may be most effective if they focus on modifying the use of fast-food outlets.The work was undertaken by the Centre for Diet and Activity Research, a UK Clinical Research Collaboration Public Health Research Centre of Excellence. Funding from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration [RG72218], is gratefully acknowledged. In addition, Dr. Penney’s PhD studentship is generously supported by the Cambridge International Scholarship, a scheme funded by the Cambridge Commonwealth, European, and International Trust

Change in diet in the period from adolescence to early adulthood: a systematic scoping review of longitudinal studies

Late adolescence to early adulthood is a period of lifestyle change and personal development which may influence dietary behaviour. Understanding dietary trajectories across this age range may help in targeting interventions appropriately. This scoping review aimed to assess how longitudinal change in diet is conceptualised and measured between the ages of 13 to 30.We searched Medline, SCOPUS, Embase, PsycInfo (EBSCO), ASSIA, Sportdiscus, and Web of Science Core Collection (January 2016) using search terms combining diet outcomes, longitudinal methods and indicators of adolescent or young adult age. Titles and abstracts were screened and data extracted following published guidelines for scoping reviews. Data were analysed to summarize key data on each study and map availability of longitudinal data on macronutrients and food groups by age of study participants.We identified 98 papers reporting on 40 studies. Longitudinal dietary data were available on intake of energy, key macronutrients and several food groups, but this data had significant gaps and limitations. Most studies provided only two or three waves of data within the age range of interest and few studies reported data collected beyond the early twenties. A range of dietary assessment methods were used, with greater use of less comprehensive dietary assessment methods among studies reporting food group intakes.Despite limited availability of longitudinal data to aid understanding of dietary trajectories across this age range, this scoping review identified areas with scope for further evidence synthesis. We identified a paucity of longitudinal data continuing into the mid and late twenties, variability in (quality of) dietary assessment methods, and a large variety of macronutrients and food groups studied. Advances in dietary assessment methodologies as well as increased use of social media may facilitate new data collection to further understanding of changing diet across this life stage

Anticipatory changes in British household purchases of soft drinks associated with the announcement of the Soft Drinks Industry Levy: A controlled interrupted time series analysis

This is the final version. Available on open access from the Public Library of Science via the DOI in this recordData Availability: The statistical code for the analyses are available from https://github.com/MRC-Epid/SDILEvaluation. Kantar Worldpanel data are not publicly available but can be purchased from Kantar Worldpanel (http://www.kantarworldpanel.com). The authors are not legally permitted to share the data used for this study, but interested parties may contact Kantar WorldPanel representative Sean Cannon to inquire about accessing this proprietary data ([email protected]).Background Sugar-sweetened beverage (SSB) consumption is positively associated with obesity, type 2 diabetes, and cardiovascular disease. The World Health Organization recommends that member states implement effective taxes on SSBs to reduce consumption. The United Kingdom Soft Drinks Industry Levy (SDIL) is a two-tiered tax, announced in March 2016 and implemented in April 2018. Drinks with >8 g of sugar per 100 ml (higher levy tier) are taxed at £0.24 per litre, drinks with >5 to 1.2% alcohol by volume are exempt. We aimed to determine if the announcement of the SDIL was associated with anticipatory changes in purchases of soft drinks prior to implementation of the SDIL in April 2018. We explored differences in the volume of and amount of sugar in household purchases of drinks in each levy tier at 2 years post announcement. Methods and findings We used controlled interrupted time series to compare observed changes associated with the announcement of the SDIL to the counterfactual scenario of no announcement. We used data from Kantar Worldpanel, a commercial household purchasing panel with approximately 30,000 British members that includes linked nutritional data on purchases. We conducted separate analyses for drinks liable for the SDIL in the higher, lower, and no-levy tiers controlling with household purchase volumes of toiletries. At 2 years post announcement, there was no difference in volume of or sugar from purchases of higher-levy-tier drinks compared to the counterfactual of no announcement. In contrast, a reversal of the existing upward trend in volume (ml) of and amount of sugar (g) in purchases of lower-levy-tier drinks was seen. These changes led to a −96.1 ml (95% confidence interval [CI] −144.2 to −48.0) reduction in volume and −6.4 g (95% CI −9.8 to −3.1) reduction in sugar purchased in these drinks per household per week. There was a reversal of the existing downward trend in the amount of sugar in household purchases of the no-levy drinks but no change in volume purchased. At 2 years post announcement, these changes led to a 6.1 g (95% CI 3.9–8.2) increase in sugar purchased in these drinks per household per week. There was no evidence that volume of or amount of sugar in purchases of all drinks combined was different from the counterfactual. This is an observational study, and changes other than the SDIL may have been responsible for the results reported. Purchases consumed outside of the home were not accounted for. Conclusions The announcement of the UK SDIL was associated with reductions in volume and sugar purchased in lower-levy-tier drinks before implementation. These were offset by increases in sugar purchased from no-levy drinks. These findings may reflect reformulation of drinks from the lower levy to no-levy tier with removal of some but not all sugar, alongside changes in consumer attitudes and beliefs.Centre for Diet and Activity Research (CEDAR)Medical Research Council (MRC)National Institute for Health Research (NIHR

Risk communication and informed consent in the medical tourism industry: A thematic content analysis of canadian broker websites

<p>Abstract</p> <p>Background</p> <p>Medical tourism, thought of as patients seeking non-emergency medical care outside of their home countries, is a growing industry worldwide. Canadians are amongst those engaging in medical tourism, and many are helped in the process of accessing care abroad by medical tourism brokers - agents who specialize in making international medical care arrangements for patients. As a key source of information for these patients, brokers are likely to play an important role in communicating the risks and benefits of undergoing surgery or other procedures abroad to their clientele. This raises important ethical concerns regarding processes such as informed consent and the liability of brokers in the event that complications arise from procedures. The purpose of this article is to examine the language, information, and online marketing of Canadian medical tourism brokers' websites in light of such ethical concerns.</p> <p>Methods</p> <p>An exhaustive online search using multiple search engines and keywords was performed to compile a comprehensive directory of English-language Canadian medical tourism brokerage websites. These websites were examined using thematic content analysis, which included identifying informational themes, generating frequency counts of these themes, and comparing trends in these counts to the established literature.</p> <p>Results</p> <p>Seventeen websites were identified for inclusion in this study. It was found that Canadian medical tourism broker websites varied widely in scope, content, professionalism and depth of information. Three themes emerged from the thematic content analysis: training and accreditation, risk communication, and business dimensions. Third party accreditation bodies of debatable regulatory value were regularly mentioned on the reviewed websites, and discussion of surgical risk was absent on 47% of the websites reviewed, with limited discussion of risk on the remaining ones. Terminology describing brokers' roles was somewhat inconsistent across the websites. Finally, brokers' roles in follow up care, their prices, and the speed of surgery were the most commonly included business dimensions on the reviewed websites.</p> <p>Conclusion</p> <p>Canadian medical tourism brokers currently lack a common standard of care and accreditation, and are widely lacking in providing adequate risk communication for potential medical tourists. This has implications for the informed consent and consequent safety of Canadian medical tourists.</p

Assessing stability and change of four performance measures: a longitudinal study evaluating outcome following total hip and knee arthroplasty

BACKGROUND: Physical performance measures play an important role in the measurement of outcome in patients undergoing hip and knee arthroplasty. However, many of the commonly used measures lack information on their psychometric properties in this population. The purposes of this study were to examine the reliability and sensitivity to change of the six minute walk test (6MWT), timed up and go test (TUG), stair measure (ST), and a fast self-paced walk test (SPWT) in patients with hip or knee osteoarthritis (OA) who subsequently underwent total joint arthroplasty. METHODS: A sample of convenience of 150 eligible patients, part of an ongoing, larger observational study, was selected. This included 69 subjects who had a diagnosis of hip OA and 81 diagnosed with knee OA with an overall mean age of 63.7 ± 10.7 years. Test-retest reliability, using Shrout and Fleiss Type 2,1 intraclass correlations (ICCs), was assessed preoperatively in a sub-sample of 21 patients at 3 time points during the waiting period prior to surgery. Error associated with the measures' scores and the minimal detectable change at the 90% confidence level was determined. A construct validation process was applied to evaluate the measures' abilities to detect deterioration and improvement at two different time points post-operatively. The standardized response mean (SRM) was used to quantify change for all measures for the two change intervals. Bootstrapping was used to estimate the 95% confidence intervals (CI) for the SRMs. RESULTS: The ICCs (95% CI) were as follows: 6MWT 0.94 (0.88,0.98), TUG 0.75 (0.51, 0.89), ST 0.90 (0.79, 0.96), and the SPWT 0.91 (0.81, 0.97). Standardized response means varied from .79 to 1.98, being greatest for the ST and 6MWT over the studied time intervals. CONCLUSIONS: The test-retest estimates of the 6MWT, ST, and the SPWT met the requisite standards for making decisions at the individual patient level. All measures were responsive to detecting deterioration and improvement in the early postoperative period

The epidemiology of bacterial vaginosis in relation to sexual behaviour

<p>Abstract</p> <p>Background</p> <p>Bacterial vaginosis (BV) has been most consistently linked to sexual behaviour, and the epidemiological profile of BV mirrors that of established sexually transmitted infections (STIs). It remains a matter of debate however whether BV pathogenesis does actually involve sexual transmission of pathogenic micro-organisms from men to women. We therefore made a critical appraisal of the literature on BV in relation to sexual behaviour.</p> <p>Discussion</p> <p><it>G. vaginalis </it>carriage and BV occurs rarely with children, but has been observed among adolescent, even sexually non-experienced girls, contradicting that sexual transmission is a necessary prerequisite to disease acquisition. <it>G. vaginalis </it>carriage is enhanced by penetrative sexual contact but also by non-penetrative digito-genital contact and oral sex, again indicating that sex <it>per se</it>, but not necessarily coital transmission is involved. Several observations also point at female-to-male rather than at male-to-female transmission of <it>G. vaginalis</it>, presumably explaining the high concordance rates of <it>G. vaginalis </it>carriage among couples. Male antibiotic treatment has not been found to protect against BV, condom use is slightly protective, whereas male circumcision might protect against BV. BV is also common among women-who-have-sex-with-women and this relates at least in part to non-coital sexual behaviours. Though male-to-female transmission cannot be ruled out, overall there is little evidence that BV acts as an STD. Rather, we suggest BV may be considered a sexually enhanced disease (SED), with frequency of intercourse being a critical factor. This may relate to two distinct pathogenetic mechanisms: (1) in case of unprotected intercourse alkalinisation of the vaginal niche enhances a shift from lactobacilli-dominated microflora to a BV-like type of microflora and (2) in case of unprotected and protected intercourse mechanical transfer of perineal enteric bacteria is enhanced by coitus. A similar mechanism of mechanical transfer may explain the consistent link between non-coital sexual acts and BV. Similar observations supporting the SED pathogenetic model have been made for vaginal candidiasis and for urinary tract infection.</p> <p>Summary</p> <p>Though male-to-female transmission cannot be ruled out, overall there is incomplete evidence that BV acts as an STI. We believe however that BV may be considered a <it>sexually enhanced disease</it>, with frequency of intercourse being a critical factor.</p

Obesity and caries in four-to-six year old English children: a cross-sectional study.

BACKGROUND: Obesity and caries are common conditions in childhood and can have significant implications on children's wellbeing. Evidence into their association remains conflicting. Furthermore, studies examining the ssociation between obesity and caries commonly focus on individual-level determinants. The present study aimed to examine the association between obesity and caries in young English children and to determine the impact of deprivation and area-level characteristics on the distribution of the two conditions. METHODS: This was a cross-sectional study among children in Plymouth city aged four-to-six years. Anthropometric measurements included weight and height (converted to Body Mass Index centiles and z-scores), and waist circumference. Caries was assessed by using the sum of the number of teeth that were decayed, missing or filled. A questionnaire was used to obtain information on children's demographic characteristics, oral hygiene, and dietary habits. The impact of deprivation on anthropometric variables and caries was determined using Linear and Poisson regression models, respectively. Multiple logistic regression was used to assess the association between different anthropometric measures and caries. Logistic regression models were also used to examine the impact of several demographic characteristics and health behaviours on the presence of obesity and caries. RESULTS: The total sample included 347 children aged 5.10 ± 0.31 (mean ± SD). Deprivation had a significant impact on caries and BMI z-scores (p < 0.05). Neither BMI- nor waist circumference z-scores were shown to be significantly associated with dental caries. Among the neighbourhood characteristics examined, the percentage of people dependent on benefits was found to have a significant impact on caries rates (p < 0.05). Household's total annual income was inversely related to caries risk and parental educational level affected children's tooth brushing frequency. CONCLUSIONS: No associations between any measure of obesity and caries were found. However, deprivation affected both obesity and caries, thus highlighting the need to prioritise disadvantaged children in future prevention programmes