Obesity persistence and duration dependence: evidence from a cohort of US adults (1985-2010)

Financial health and obesity

We use individual-level panel data from the English Longitudinal Survey of Ageing over the period 2004-2013 to investigate the links between financial health and obesity. We find that having no debt (high savings) is associated with a 3.6 (1.6) percentage point lower probability of having a Body Mass Index in excess of 30. Our results are robust to using different estimation methods, to measuring financial health with a subjective indicator, and adiposity with waist circumference. A lower rate of time preference and lower stress levels may be mechanisms which help to explain the association between good financial health and obesity.

BMI mobility and obesity transitions among children in Ireland

This paper examines mobility and changes in Body Mass Index (BMI) for a sample of Irish children/adolescents across three waves of the longitudinal Growing Up in Ireland dataset. Particular attention is paid to transitions across the key BMI thresholds of overweight and obesity. Analysis is carried out by gender and by maternal education. In general, mobility is observed, with intra-generational rank-rank BMI coefficients of around 0.63 compared to coefficients of around 0.77 for the mothers of the children over the same time period. Across the distribution as a whole there is relatively little variation by gender and maternal education. However there a gender difference in terms of mobility out of obesity with the Shorrocks mobility index across categories of normal weight/overweight/obesity taking a value of 0.56 for females as opposed to 0.71 for males. This relative lack of mobility is more observed in later rather than earlier adolescence.

Cardiorespiratory fitness, fatness and incident diabetes

AIMS

Increases in prevalence have led to a diabetes pandemic. Obesity and low cardiorespiratory fitness (CRF) are considered to be central mechanisms. We investigated if the effect of CRF on diabetes risk was equivalent across levels of fatness among healthy men.

METHODS

In total 4988 middle-aged Caucasian employed men free of cardiovascular disease, diabetes and cancer were included from the Copenhagen Male Study starting in 1970-71. CRF was assessed using a sub-maximal bicycle ergometer test and body mass index (BMI) was measured by height and weight. Their interaction and stratified associations with diabetes incidence were estimated in multivariable Cox-models including conventional risk factors and social class. Diabetes incidence was assessed through a national register.

RESULTS

During 44 years of follow-up, 518 (10.4%) incident cases of diabetes occurred. In the multi-adjusted model, the obese had a significantly higher risk of diabetes compared to normal weight men (Hazard Ratio (HR):4.89; 95% CI: 3.62-6.61) and CRF was significantly inversely associated with diabetes (HR:0.86; 95% CI: 0.75-0.98 per 10-unit increase in ml/kg/min¹ CRF). A significant multi-adjusted interaction between CRF, BMI and diabetes was found (p=0.009). The stratified multi-adjusted analyses on BMI showed a significantly stronger reduced risk of diabetes per 10-unit increase in ml/kg/min¹ of CRF among the obese (HR:0.58; CI: 0.38-0.89), but a weaker association among overweight (HR:0.86; CI: 0.71-1.03) and normal weight (HR:0.97; CI: 0.76-1.23).

CONCLUSION

High CRF has a stronger protective effect on diabetes among obese than among normal weight men, supporting the recommendation of fitness-enhancing physical activity for preventing diabetes among the obese.

Health and economic benefits of reducing sugar intake in the USA, including effects via non-alcoholic fatty liver disease: a microsimulation model

OBJECTIVES

Excessive consumption of added sugars in the human diet has been associated with obesity, type 2 diabetes (T2D), coronary heart disease (CHD) and other elements of the metabolic syndrome. Recent studies have shown that non-alcoholic fatty liver disease (NAFLD) is a critical pathway to metabolic syndrome. This model assesses the health and economic benefits of interventions aimed at reducing intake of added sugars.

METHODS

Using data from US National Health Surveys and current literature, we simulated an open cohort, for the period 2015-2035. We constructed a microsimulation model with Markov chains for NAFLD (including steatosis, non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC)), body mass index, T2D and CHD. We assessed reductions in population disease prevalence, disease-attributable disability-adjusted life years (DALYs) and costs, with interventions that reduce added sugars consumption by either 20% or 50%.

FINDINGS

The model estimated that a 20% reduction in added sugars intake will reduce prevalence of hepatic steatosis, NASH, cirrhosis, HCC, obesity, T2D and CHD. Incidence of T2D and CHD would be expected to decrease by 19.9 (95% CI 12.8 to 27.0) and 9.4 (95% CI 3.1 to 15.8) cases per 100 000 people after 20 years, respectively. A 20% reduction in consumption is also projected to annually avert 0.767 million (M) DALYs (95% CI 0.757M to 0.777M) and a total of US$10.3 billion (B) (95% CI 10.2B to 10.4B) in discounted direct medical costs by 2035. These effects increased proportionally when added sugars intake were reduced by 50%.

CONCLUSIONS

The decrease in incidence and prevalence of disease is similar to results in other models, but averted costs and DALYs were higher, mainly due to inclusion of NAFLD and CHD. The model suggests that efforts to reduce consumption of added sugars may result in significant public health and economic benefits.

Duration of US Residence and Obesity Risk in NYC Chinese Immigrants

We evaluated whether duration of time in the US is associated with obesity risk in NYC Chinese immigrants. We analyzed cross-sectional survey data on 2072 men and women. Duration of US residence was categorized into ≤5, 6-15, and 15 years and over. Obesity was defined using WHO Asian standards: BMI of 27.5 kg/m(2) or greater. Diet and physical activity (PA) were assessed as potential explanatory variables. After adjusting for covariates, increased time in the US was associated with an increased obesity risk (OR 1.49; 95 % CI 1.06, 2.08 for 15 years or more vs. ≤5 years); and in separate analysis, with having reported no work related PA (OR 0.76; 95 % CI 0.59, 0.99). Findings suggest that increased time living in the US is associated with an increased obesity risk, a finding possibly explained by a shift to more sedentary lifestyle characteristic of the transition of immigrants to the US.

Duration of US Residence Is Associated With Overweight Risk in Filipino Immigrants Living in New York Metro Area

We examined the association between years living in the United States and overweight risk among a community sample of Filipino adult immigrants living in the New York metropolitan area. We found a significant and adverse association between years living in the United States and overweight risk. Compared with Filipinos who lived in the United States less than 5 years, those who lived in the United States 10 years or longer had a higher overweight risk; this association was present only among Filipinos who migrated to New York metropolitan area at 30 years of age or younger. Studies on causal mechanisms explaining this pattern are needed.

Persistence in body mass index in a recent cohort of US children

While childhood obesity has become a significant public health concern over the last few decades, and underweight children continue to be a concern, knowledge pertaining to the origins of or persistence in childhood anthropometric measures is incomplete. Here, we utilize several nonparametric metrics to assess the evolution of weight and body mass index (BMI) across the entire distribution during early childhood. We find that movements within the distribution of weight - both upward and downward - are quite high prior to primary school and then decline noticeably. For BMI, we find that movements within the distribution - both upward and downward - are highest at the start of kindergarten and at the start of middle school. However, there are important sources of heterogeneity, including race, gender, and age that should prove insightful to researchers and policymakers. For instance, comparing males versus females who are initially in the bottom quartile of the distribution of BMI, we find that males have a higher probability of moving up at least 10 percentile points between kindergarten and eighth grade (53% versus 50%). Comparisons among racial groups indicate that whites who are initially in the top quartile of the distribution of BMI have a higher probability of moving down at least 10 percentile points between kindergarten and eighth grade than blacks and Hispanics (46% versus 37% and 40%, respectively).

Taking time seriously: a call to action in mental health research

Sociological research on mental health focuses on a multitude of dynamic processes, including changes in psychological symptoms or the onset of a mental disorder, the course and outcome of mental health problems, and the associations of mental health with a wide variety of time-varying social risk and protective factors. I argue that scholars studying mental health have, thus far, only scratched the surface of the temporal dynamics upon which mental health and illness rest. Two broad research issues are reviewed to illustrate important temporal issues that have been neglected or understudied in mental health research: (1) specific dimensions of temporality, which focus on dynamic processes at the individual level, and (2) the age-period-cohort model, which focuses on mental health at the population level. Priority topics for future research that takes time seriously are recommended.

Life cycle development of obesity and its determinants in six European countries

This paper empirically examines the effect of parents' and individuals' own socioeconomic status on overweight and obesity, and investigates how this effect changes over the life cycle. The impact of individuals' health behaviours on their obesity status later in life is also studied. We use data from Denmark, Finland, France, Greece, the Netherlands and the U.K. in which 4595 individuals aged 50-65 are surveyed and where individuals' height and weight at different ages (25, 35, 45 and current age) are available. We perform "repeated cross-sections" analyses as well as dynamic probit analyses of the individuals' obesity histories. We contribute to the literature by examining the role of a variety of obesity determinants over the whole life cycle, not only over a certain portion of individuals' lives. Key findings are: (i) parents' socioeconomic status predicts obesity in early adulthood whereas the individual's own socioeconomic status as adult is more important in explaining obesity at later stages of the life cycle, (ii) changes in obesity status are associated with changes in health behaviours, (iii) obesity in late adulthood is strongly and positively correlated with overweight and obesity in younger ages, and (iv) cross-country differences in obesity and overweight largely remain after controlling for parental and childhood factors and individuals' health behaviours.