Diet and physical activity as possible mediators of the association between educational attainment and body mass index gain among Australian adults

How socioeconomic status affects weight status through health-related lifestyles: a latent class analysis

AIMS

Obesity levels have increased worldwide with serious public health concerns. However, weight status is related to socioeconomic status (SES), which may also influence health-related lifestyles. Here, we study the association between SES and obesity mediated by diet and physical activity.

METHODS AND RESULTS

Using cross-sectional data from 2006, 2011, 2014, and 2017 Spanish health surveys (the final sample consisted of 61 768 adults aged between 18 and 64 years), we conducted a latent class analysis to estimate health-related lifestyle clusters (based on dietary patterns and physical activity) and mediation analyses to evaluate the association of SES and obesity through the clustering of health-related lifestyles. In both men and women, SES was inversely related to obesity (P < 0.001) and positively related to healthier lifestyle classes (P < 0.001). Obesity was inversely related to healthier lifestyle classes (P < 0.001). A small-although significant-proportion mediated by the clustering of lifestyles was found as follows: 4.9%, 95% CI (6.6%, 3.2%) in men and 2.3%, 95% CI (3.4%, 1.3%) in women for educational attainment, 5.3%, 95% CI (7.2%, 3.6%) in men and 2.0%, 95% CI (2.9%, 1.1%) in women for occupational social class, and 4.9%, 95% CI (6.5%, 3.1%) and 1.9%, 95% CI (2.9%, 1.1%) combining the above two SES indicators.

CONCLUSIONS

SES is related to obesity through clustering health-related lifestyles, with greater emphasis on men. However, the complex relationship between SES and weight status also suggests other indicators that contribute to the social gradient of obesity.

Ultraprocessed Foods and Obesity Risk: A Critical Review of Reported Mechanisms

Epidemiologic evidence supports a positive association between ultraprocessed food (UPF) consumption and body mass index. This has led to recommendations to avoid UPFs despite very limited evidence establishing causality. Many mechanisms have been proposed, and this review critically aimed to evaluate selected possibilities for specificity, clarity, and consistency related to food choice (i.e., low cost, shelf-life, food packaging, hyperpalatability, and stimulation of hunger/suppression of fullness); food composition (i.e., macronutrients, food texture, added sugar, fat and salt, energy density, low-calorie sweeteners, and additives); and digestive processes (i.e., oral processing/eating rate, gastric emptying time, gastrointestinal transit time, and microbiome). For some purported mechanisms (e.g., fiber content, texture, gastric emptying, and intestinal transit time), data directly contrasting the effects of UPF and non-UPF intake on the indices of appetite, food intake, and adiposity are available and do not support a unique contribution of UPFs. In other instances, data are not available (e.g., microbiome and food additives) or are insufficient (e.g., packaging, food cost, shelf-life, macronutrient intake, and appetite stimulation) to judge the benefits versus the risks of UPF avoidance. There are yet other evoked mechanisms in which the preponderance of evidence indicates ingredients in UPFs actually moderate body weight (e.g., low-calorie sweetener use for weight management; beverage consumption as it dilutes energy density; and higher fat content because it reduces glycemic responses). Because avoidance of UPFs holds potential adverse effects (e.g., reduced diet quality, increased risk of food poisoning, and food wastage), it is imprudent to make recommendations regarding their role in diets before causality and plausible mechanisms have been verified.

Parental Education May Differentially Impact Pediatric Inflammatory Bowel Disease Phenotype Risk

BACKGROUND

The incidence of pediatric inflammatory bowel diseases (PIBDs: Crohn's disease [CD], ulcerative colitis [UC]) is on the rise around the world. Yet, the critical risk factors for this rising incidence are not well understood. Demographic characteristics of PIBD may improve our understanding of their developmental origins and aid in prevention.

METHODS

Four hundred eighty-eight consecutive PIBD patients diagnosed at Texas Children's Hospital from 13 counties around Houston were studied. An annual incidence map was created by ZIP code of residence at diagnosis by using ArcGIS and the American Community Survey from the US Census Bureau. Correlation between demographic variables and PIBD incidence was examined. A model to explain incidence from different health factors was created in R.

RESULTS

Hispanic children were more likely to be diagnosed with UC (P < 0.01) and unclassified IBD (IBD-U) (P < 0.03) compared with other races/ethnicities. A significant positive correlation (r = 0.35, P < 0.0001) between median household income and PIBD incidence was observed (UC: r = 0.23, P < 0.0001; CD: r = 0.22, P = 0.0004). ZIP codes with majority college-educated adults had a higher incidence of PIBD than ZIP codes with majority high school-educated adults (P < 0.0001). Pediatric cases with CD were more common in ZIP codes where the majority of adults were college educated (P < 0.0001). Pediatric cases with UC, however, were more common in ZIP codes where the majority of adults were high school educated (P = 0.0036).

CONCLUSIONS

Hispanic children more commonly present with UC and IBD-U in southern USA. Household income and/or adult education-related environmental/dietary differences may be important in the developmental origins of PIBD in large metro areas, such as Houston.

Intense Sweeteners, Taste Receptors and the Gut Microbiome: A Metabolic Health Perspective

Intense sweeteners (IS) are often marketed as a healthier alternative to sugars, with the potential to aid in combating the worldwide rise of diabetes and obesity. However, their use has been counterintuitively associated with impaired glucose homeostasis, weight gain and altered gut microbiota. The nature of these associations, and the mechanisms responsible, are yet to be fully elucidated. Differences in their interaction with taste receptors may be a potential explanatory factor. Like sugars, IS stimulate sweet taste receptors, but due to their diverse structures, some are also able to stimulate bitter taste receptors. These receptors are expressed in the oral cavity and extra-orally, including throughout the gastrointestinal tract. They are involved in the modulation of appetite, glucose homeostasis and gut motility. Therefore, taste genotypes resulting in functional receptor changes and altered receptor expression levels may be associated with metabolic conditions. IS and taste receptors may both interact with the gastrointestinal microbiome, and their interactions may potentially explain the relationship between IS use, obesity and metabolic outcomes. While these elements are often studied in isolation, the potential interactions remain unexplored. Here, the current evidence of the relationship between IS use, obesity and metabolic outcomes is presented, and the potential roles for interactions with taste receptors and the gastrointestinal microbiota in modulating these relationships are explored.

Non-nutritive Sweeteners and Glycaemic Control

PURPOSE OF REVIEW

The consumption of foods and beverages containing non-nutritive sweeteners (NNS) has increased worldwide over the last three decades. Consumers' choice of NNS rather than sugar or other nutritive sweeteners may be attributable to their potential to reduce weight gain.

RECENT FINDINGS

It is not clear what the effects of NNS consumption are on glycaemic control and the incidence of type 2 diabetes. This review aims to examine this question in epidemiological, human intervention and animal studies. It is not clear that NNS consumption has an effect on the incidence of type 2 diabetes or on glycaemic control even though there is some evidence for the modification of the microbiome and for interaction with sweet taste receptors in the oral cavity and the intestines' modification of secretion of glucagon-like peptide-1 (GLP-1), peptide YY (PYY), ghrelin and glucose-dependent insulinotropic polypeptide (GIP), which may affect glycaemia following consumption of NNS. In conclusion, long-term studies of NNS consumption are required to draw a firm conclusion about the role of NNS consumption on glycaemic control.

The Contribution of Diet Quality to Socioeconomic Inequalities in Obesity: A Population-based Study of Swiss Adults

Socioeconomically disadvantaged people are disproportionally more likely to develop obesity and obesity-related diseases. However, it remains unclear to what extent diet quality contributes to socioeconomic inequalities in obesity. We aimed to assess the role of diet quality in the association between socioeconomic status (SES) and obesity. Data originated from the national nutrition survey, a cross-sectional sample of the adult Swiss population (N = 1860). We used education and income as proxies for SES; calculated the Alternate Healthy Eating Index (AHEI) as a measure of diet quality; and used body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) as obesity markers. We applied counterfactual mediation modelling to generate odds ratios, 95% confidence intervals, and the proportion mediated by diet quality. Individuals with less than a tertiary education were two to three times more likely to be obese, regardless of the marker (OR (95% CI): 3.36 (2.01, 5.66) using BMI; 2.44 (1.58, 3.75) using WC; 2.48 (1.63, 3.78) using WHR; and 2.04 (1.43, 2.96) using WHtR). The proportion of the association between educational level and obesity that was mediated by diet quality was 22.1% using BMI, 26.6% using WC, 31.4% using WHtR, and 35.8% using WHR. Similar findings were observed for income. Our findings suggest that diet quality substantially contributes to socioeconomic inequalities in obesity while it does not fully explain them. Focusing efforts on improving the diet quality of disadvantaged groups could help reduce social inequalities in obesity.

Variation in the physical activity environment according to area-level socio-economic position-A systematic review

Physical inactivity is a major contributing factor to obesity, and both follow a socio-economic gradient. This systematic review aims to identify whether the physical activity environment varies by socio-economic position (SEP), which may contribute to socio-economic patterning of physical activity behaviours, and in turn, obesity levels. Six databases were searched. Studies were included if they compared an objectively measured aspect of the physical activity environment between areas of differing SEP in a high-income country. Two independent reviewers screened all papers. Results were classified according to the physical activity environment analysed: walkability/bikeability, green space, and recreational facilities. Fifty-nine studies met the inclusion criteria. A greater number of positive compared with negative associations were found between SEP and green space, whereas there were marginally more negative than positive associations between SEP and walkability/bikeability and recreational facilities. A high number of mixed and null results were found across all categories. With a high number of mixed and null results, clear socio-economic patterning in the presence of physical activity environments in high-income countries was not evident in this systematic review. Heterogeneity across studies in the measures used for both SEP and physical activity environments may have contributed to this result.

Socioeconomic Disadvantage across the Life Course Is Associated with Diet Quality in Young Adulthood

Socioeconomic position (SEP) is a key determinant of diet quality across the life course. Young adulthood is a unique period of transition where dietary inequities between groups with lower and higher SEP may widen. This study investigated associations between SEP in both childhood and young adulthood and diet quality in young adulthood. Data from 1949 Canadian young adults aged 18⁻30 who participated in the Canada Food Study were analyzed. Healthy Eating Index⁻2015 (HEI-2015) scores were calculated based on one 24-hour dietary recall. Childhood and young adult SEP were represented by self-report of participants' parent(s)' and their own highest educational level, respectively. Linear regression was used to examine associations between childhood and adult SEP and adult HEI-2015 score. Mediation analyses examined whether adult SEP mediated the relationship between childhood SEP and adult HEI-2015 score. Lower SEPs in childhood and adulthood were each associated with lower HEI-2015 scores in young adulthood. Adult SEP mediated up to 13.0% of the association between childhood SEP and adult HEI-2015 scores. Study findings provide support for key life course hypotheses and suggest latent, pathway, and cumulative effects of SEP across the early life course in shaping the socioeconomic patterning of diet quality in young adulthood.