Nutrition, Lifestyle, Genes and Metabolome - A Biosocial Cohort Study of Obesity in Young Adults from Urban Peru

ODA compliance: Our unique approach to identify novel obesity markers uses the Poverty Map to select urban clusters and also targets health inequalities occurring within a cohort of the population that must be safeguarded in the short term for Peru's social and poverty uplifts to be sustainable in the long term. Hence, any benefits arising from this work will be communicated to the public, health professionals and government organisations who will inform public health policy on strategies to reduce the burden of obesity. Through the understanding gained in this study, the aim will be to influence government policies that will have a positive impact on the diet of the poorest population, aiming to attenuate an obesity epidemic resulting from urbanisation, helping Peru improve in particular sustainable development goals 1, 3, 11 and 17.
Summary: In Peru, the prevalence of overweight and obesity is increasing and it varies according to area of residence and socioeconomic position, with the highest prevalence reported in urban areas. Some of the reasons for higher rates of obesity in urban areas could be higher caloric intake and lower levels of physical activity. However there are various other biological and non-biological factors that are likely to contribute to the increasing prevalence of obesity in the urban population. Young Lives Study (YLS) is one of the largest population based study in low-middle-income-countries that has tracked the lives of 2,000 children in Peru over 15 years. Previous YLS studies in Peru have shown a steady increase in obesity prevalence among adolescents. However, studies investigating the progression from obesity to the development of non-communicable diseases (NCDs) such as diabetes and cardiovascular disease (CVD) are limited in Peru and hence, we will conduct SONGS (Study of Obesity, Nutrition, Genes and Social factors), which will be an expansion of the baseline data of YLS and introduce new empirical perspectives to discover novel factors of obesity. The main aim is to understand the impact of specific factors (dietary intake, lifestyle factors such as physical activity, genetic factors, physical places of residence, food preference and metabolic biomarkers) on obesity in the Peruvian population. Also, this study will shed new light on the socioeconomic determinants of overweight and obesity and gender disparities in the development of obesity during infancy, childhood and adolescence. To date, there is no study in Peru that has a follow-up time of 19 years that has examined biological and non-biological markers of obesity-related NCDs under different geographical settings.
The first step will be to collect information on dietary intake, food choice, lifestyle, living conditions and the place of residence of 1,000 adolescents from the YLS living in urban areas of Peru. As part of the survey, we will also collect blood samples for biological analysis which includes measuring the levels of important biomarkers that are shown to be abnormal in the blood of obese individuals. In addition, we will examine the impact of genes that have been previously shown to predispose individuals to obesity in other populations, and the combined effect of genes, diet and other lifestyle factors on obesity. We will also examine the levels of metabolic biomarkers which are formed in or necessary for metabolism to see whether the levels are higher in people who are obese. We will investigate the link between food choice and dietary intake and examine whether this link is influenced by genetic factors and physical places of residence. These analyses will help us to identify novel markers which can serve as predictive markers for adult obesity and NCDs. Throughout this project we will ensure communication across the key parts of the stakeholder spectrum including the scientific community, those involved in providing public health nutrition advice, health professionals, policymakers, industry and the public.

Young Lives (YLS), a longitudinal study of childhood poverty that has tracked the lives of 2,000 children in Peru over 15 years, has shown that prevalence of childhood and adolescent obesity is increasing in all sections of the population, especially in urban areas and among the better off. To date, there has been no study investigating the role of biosocial factors on obesity in Peru. Lifestyle, nutrition, genetics and metabolome have been implicated in creating an obesogenic environment and hence, SONGS (Study of Obesity, Nutrition, Genes and Social factors) will use a biosocial approach to examine the impact of dietary patterns, lifestyle, genetic factors, physical places of residence, sensory perception of foods and the metabolome on obesity-related outcomes in 1,000 urban YLS participants aged 19 from 10 clusters of the previous rounds of YLS. The role of diet, physical activity, residential neighbourhood, sensory perception and food preference phenotypes in shaping participants' life course trajectories, dietary intake and health status will be assessed. Genetic risk score, generated from a previously identified genome-wide association study which discovered BMI-related genetic variants, will be tested for its association with obesity and interaction with lifestyle and social factors. The metabolic signature of blood will also be characterised to assess the impact of these factors on health outcomes. Finally, the impact of obesity trajectories on the risk of developing non-communicable diseases will be examined. This biosocial cohort study in Peru will provide a platform from which to identify novel biosocial markers that can be used as early predictors of adult obesity and cardiovascular risk. Through the understanding gained in this study, we aim to influence government policies that will have a positive impact on the diet of the poorest population, aiming to attenuate an obesity epidemic resulting from urbanisation.

Obesity has become an important public health concern as it is associated with an increased risk of developing several non-communicable diseases. Peru is no exception to the growing problem of common and childhood obesity. Public health actions to reduce obesity have mostly focused on individuals, encouraging them to eat healthy foods and exercise more. However, these strategies are failing as not a single population has succeeded in reducing obesity prevalence in the last 30 years. In Peru, a law to promote healthy food for children/adolescents was created in 2013; its aims included the introduction of nutritional education and access to healthy food at schools, regulation of food advertisement, and the creation of the National Observatory of Nutrition. Despite this, there has been little progress towards a more active agenda.
With 56% of its population still living in informality, the OECD puts Peru in the highest category of its international classification of informal economies. This means most people have no job/social security and rely on a heavily under-resourced national health system. Although Peru has made progress in lifting people out of poverty and creating a new middle class, the current global uncertainty and the escalating dollar is stalling progress for all emerging markets, with the risk of reversing past progress. The most vulnerable amongst this 'unstable' new middle class, are the young. This proposal not only uses the Poverty Map to select urban clusters, but also targets health inequalities occurring to a cohort of the population that must be safeguarded in the short term for Peru's social and poverty uplifts to be sustainable in the long term. Through the understanding gained in SONGS project, the aim will be to develop government policies that will have a positive impact on the diet of the poorest population, aiming to reduce obesity epidemic resulting from urbanisation and promoting development, in particular sustainable development goals 1, 3, 11 and 17.
At the national level, our primary beneficiaries are: Ministry of Health, NIH, Observatory of Nutrition, Ministry of Education and Ministry of Social Development and Social Inclusion, who will aim to increase capability to develop more targeted interventions or strategies to sub-populations in Peru which will lead to the implementation of policies towards obesity prevention. In addition, families with children living in Peru will be benefitted from the nutrition/dietary advice given by the health professionals/nutrition practitioners. Furthermore, the findings from our study will be beneficial to human nutritionists who will be able to develop randomized trials of nutritional interventions to examine the causality between unhealthy lifestyle and obesity-related outcomes.
Given Peru's context (rapid urbanisation, high levels of malnutrition and increasing obesity prevalence), SONGS has the potential to become an excellent case study for other LMICs. Therefore, we will also target international beneficiaries (DfID, World Food Organization, UNICEF, Inter-American Development Bank, and World Bank), who might use our findings to change their policies and practices. For example, in 2016, YLS Peru data was used in the World Bank report 'Left Behind: Chronic Poverty in Latin America and the Caribbean' to provide insights into intergenerational poverty that would have been difficult to obtain through other non-longitudinal research.
YLS quantitative data is publicly archived via the UK Data Service (UKDS), and is internationally accessible. Public archiving is not common, especially in LMICs. In addition to the public archive, YLS makes considerable efforts to help people actually use the data. Data is released on CD-ROM to facilitate its use by those who do not have internet access. YLS country teams distribute the data directly to local researchers and also run training sessions on how to use the data and to increase data usage in the study countries.