This work-area, led by Lauren Lissner and Anna Winkvist, will focus on epidemiology of obesity with attention to stages of the lifecycle that may be pivotal in the natural history of obesity and/or or for the development of health sequellae. These are: birth, childhood, pregnancy/post pregnancy, middle age/menopause, and during the later years of life. Local collaborators in this work area are from the Departments of: Public Health and Community Medicine; Clinical Nutrition; Neurosciences, Pediatrics; and the Institute of Food, Health and Environment, all at Göteborg University. Several population based studies will be the basis for this work; most of these are local studies, others are Nordic and international collaborations. Finally, the research group includes several biostatisticians who are investigating new approaches for utilizing the local longitudinal data bases. Numerous methodological issues are relevant when repeated measures are available reflecting weight development with a lifelong perspective.
Studies of Infants
The first study included in this work package is a meta-regression study employing data from several Nordic studies, including the Population Study of Women in Gothenburg. We recently have initated standardized analyses on population-based studies from Denmark, Sweden, Finland, Iceland and Norway, all of which have measured birthweights, socioeconomic indicators, and measures of obesity later in life. We are currently planning two obesity-related analyses, one involving early influences on obesity and the other studying whether socioeconomic influences are mediating the former associations. This collaboration is supported in part by a grant from the Nordic Research Council and represents one of the largest existing data bases with birth data, longitudinal followup, and ascertainment of cardiovascular outcomes or risk markers.
Studies of Children
The next work area is based on a combined childhood obesity surveillance and intervention program. One arm of this project will monitor trends in the obesity epidemic among 10 year olds, with a special socioeconomic focus; at the same time an intervention representing the Swedish site for a European collaboration started data collection this fall. In other words, this work area simultaneously conducts school-based surveillance 10-year olds with evaluation of the impact of a large school-based intervention of 4 and 6 year olds. Children in the intervention (and control groups) will routinely followed up at age 10 years, at their school examinations. Sweden is one of the few countries that has the possibility of integrating local surveillance with such an intervention. A secondary aim of this part of the project is to use longitudinal data from the 1974 birth cohort to test currently adapted IOTF definitions of childhood obesity with real data collected into adulthood. This work is a collaboration between the the Departments of Pediatrics and Public Health/Community Medicine. This group is also joining a WHO Childhood Obesity Surveillance Project, which together with other European countries, will collect anthropometric data on representative samples of schoolchildren, in 2-year cycles.
Studies of young adults
The pregnancy/post-pregnancy period is anecdotally associated with the development of obesity problems in women, although there is little research on this phenomenon at the population level. For this purpose, EpiLife researchers will conduct research work on two fronts: a collaboration with the Norwegian Mother and Child birth cohort study (MOBA); and a local intervention among Swedish women recruited in the post-partum period. MOBA is a unique observational study of 100000 Norwegian births that includes data on determinants of post-pregnancy weight retention in women. We are currently developing a plan for a study on psychosocial predictors of post-partum weight retention (with Prof. Margaretha Haugen). This type of study may be considered a natural complement to development of targeted and community-based interventions in women post-partum to prevent onset of obesity. Such a program is being developed by Winkvist in collaboration with the Clinical Nutrition group. The collaboration with MOBA will be conducted in parallel with the similar Danish National Birth Cohort study (DNBC) where we have been investigating relations between maternal obesity, early cessation of lactation, and effects on subsequent weight retention.
Studies in Middle Age
At this stage in life overweight and obesity become associated with comorbidity in a significant fraction of the population. Here, we will be focusing on factors during mid-life that predispose the development of obesity, as well as cardiovascular outcomes attributed to obesity. Susceptibility factors will include psychosocial, lifestyle (diet/physical activity), genetic, as well as interactions among them. We are also collaborating with the Västerbotten VIP study to examine associations between different fat types and subsequent weight gain in women. This is a followup previous findings in the Population Study of Women in Göteborg and more recently Nurses Health Study.
Studies in the elderly
Long-term studies in the elderly are a major interest area for Göteborg epidemiologic research but also represent one of our greatest challenges. For instance, the Population Study of Women in Göteborg has been conducting repeated examinations on the cohort for 40 years, which offers opportunities for methodological development in survival analyses, incorporating all available anthropometric data collected over time for each individual. Similarly the H70 study has been following elderly populations from age 70 for the rest of their lives and has similar possiblities for studying body weight development in the oldest old, in relation to survival and other competing risks of a variety of physical health outcomes. At the same time both of these studies have meticulously collected psychiatric data in order to document the development of neurodegenerative diseases. Recent collaboration with the Psychiatric Epidemiology Unit has suggested that obesity may be linked to depression and dementia later in life but results can be highly sensitive to when the anthropometric measures are taken, as well as the statistical approach chosen. Current plans are to study influences of obesity-related comorbidities, particularly diabetes, on psychiatric endpoints later in life.