Review article

Epidemiologic trends in overweight and obesity

Body mass index (BMI) is generally used to classify adiposity. Despite the fact that the consequences of adiposity for chronic health accumulate and manifest over time, most population health research exploring the implications of high BMI measures only its recent intensity. Some studies have used retrospective measures involving maximum weight, and even fewer have used BMI at multiple time points to estimate cumulative exposure to adiposity. The goal of this study was to compare BMI exposure metrics that captured different dimensions of body mass – intensity, history, and duration – in models of health indicators linked with adiposity. We used self-reported BMI of young adults (ages 18 – 33 years, n = 8,608) across 11 waves of data from the National Longitudinal Survey of Youth 1997 to evaluate eight BMI exposure metrics: most recent, maximum, mean, and median BMI, proportion of time with overweight/obesity, and excess BMI-years with overweight/obesity. We used these metrics in models of self-reported general health, chronic condition, and diabetes, and ascertained how most recent BMI performed when compared with other metrics that better capture the dynamics of BMI. The Akaike information criteria and Vuong tests were used for model comparison, and the strengths of associations were also compared. Most recent BMI was the best metric for explaining general health. Median BMI was best for explaining diabetes, with most recent BMI under-estimating the association by 13% relative to median BMI. For chronic condition, there was no clear best metric. We concluded that most recent BMI is useful for explaining health outcomes, though other metrics should also be given consideration, particularly for conditions that develop over time. Metrics that accounted for both intensity and history performed quite well, but the duration measures might be less useful.

Obesity is highly prevalent worldwide. Emerging clinical studies suggest that pre- and pro- biotic formulations may be effective interventions for the management of obesity and associated metabolic complications. The current trial was conducted to assess the effect of synbiotic supplementation on anthropometric indices, glycemic and lipid profile, blood pressure, and psychological status of adults with overweight or obesity.

This randomized double-blind, placebo-controlled trial was conducted on 60 adults with overweight or obesity. Participants were randomly assigned into two groups to receive either synbiotics (n = 30) in form of a 500 mg capsule (containing Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium bifidum plus inulin) or placebo (n = 30) for 8 weeks. The level of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FPG), insulin, body weight, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), stress, anxiety, and depression were measured at the baseline and end of the study.

In total, 59 subjects (39 men and 20 women) completed the present study. A significant between-group decrease in body weight (P = 0.03), TC (P = 0.01), TG (P = 0.02), LDL-C (P = 0.01), stress (P < 0.001), anxiety (P = 0.03), and depression (P = 0.03) was found in the synbiotic group compared to the placebo. However, synbiotics had no significant effect on HDL-C, SBP, DBP, FPG and fasting insulin concentrations, as well the BMI and WC (P < 0.05).

The present study showed that synbiotic supplementation can confer a number of health benefits including improvements in TG, TC, LDL-C, body weight, stress, anxiety, and depression to subjects that are overweight or obesity.

Iranian Registry of Clinical Trials IRCT20180201038585N3.

Cancer is a major cause of death in patients with non-alcoholic fatty liver disease (NAFLD). Obesity is a risk factor for cancers; however, the role of NAFLD in this association is unknown. We investigated the effect of NAFLD versus obesity on incident cancers.

We identified all incident cases of NAFLD in a US population between 1997-2016. Individuals with NAFLD were matched by age and sex to referent individuals from the same population (1:3) on the index diagnosis date. We ascertained the incidence of cancer after index date until death, loss to follow-up or study end. NAFLD and cancer were defined using a code-based algorithm with high validity and tested by medical record review. The association between NAFLD or obesity and cancer risk was examined using Poisson regression.

A total of 4,722 individuals with NAFLD (median age 54, 46% male) and 14,441 age- and sex-matched referent individuals were followed for a median of 8 (range 1–21) years, during which 2,224 incident cancers occurred. NAFLD was associated with 90% higher risk of malignancy: incidence rate ratio (IRR) = 1.9 (95% CI 1.3–2.7). The highest risk increase was noted in liver cancer, IRR = 2.8 (95% CI 1.6–5.1), followed by uterine IRR = 2.3 (95% CI 1.4–4.1), stomach IRR = 2.3 (95% CI 1.3–4.1), pancreas IRR = 2.0 (95% CI 1.2–3.3) and colon cancer IRR = 1.8 (95% CI 1.1–2.8). In reference to non-obese controls, NAFLD was associated with a higher risk of incident cancers (IRR = 2.0, 95% CI 1.5–2.9), while obesity alone was not (IRR = 1.0, 95% CI 0.8–1.4).

NAFLD was associated with increased cancer risk, particularity of gastrointestinal types. In the absence of NAFLD, the association between obesity and cancer risk is small, suggesting that NAFLD may be a mediator of the obesity-cancer association.

We studied the incidence of malignancies in a community cohort of adults with non-alcoholic fatty liver disease (NAFLD) in reference to age- and sex-matched adults without NAFLD. After 21 years of longitudinal follow-up, NAFLD was associated with a nearly 2-fold increase in the risk of developing cancers, predominantly of the liver, gastrointestinal tract and uterus. The association with increased cancer risk was stronger in NAFLD than obesity.

Body mass index (BMI) derived from self-reported height and weight is often used to study adiposity and its health implications. However, misestimates of BMI from self-reported data have been observed. This study adds to the literature by demonstrating how anthropometric misreporting patterns differed by sex and changed across time in a nationally representative cohort, as well as examining behavioral/psychological correlates of biases in BMI.

Misreporting of height and weight (and thus BMI) from adolescence to adulthood in the United States was studied using the National Longitudinal Study of Adolescent to Adult Health (1996–2008). Behavioral/psychological characteristics possibly associated with errors in BMI were analyzed with fixed-effects models.

Different patterns of anthropometric misreporting resulted in larger underestimation of BMI among females than males at the beginning waves, but females saw a reduction by the last wave. Males did not see such a decrease, and their error, at 0.75 BMI units by 2008, was comparable to that of females. For both sexes, body image perception was a significant predictor of biases in BMI.

From adolescence to adulthood, anthropometric reporting patterns changed, and its variation differed by sex. Nevertheless, errors in BMI were similarly associated with behavioral/psychological characteristics.

Childhood obesity remains a serious problem in the United States. Significant associated adverse incidents have been reported with sedation of children with obesity, namely hypoxemia. The objective of our study was to determine if overweight and obesity were associated with increased desaturations during procedural sedation compared with patients of healthy weight.

This was a single-center retrospective chart review of data from a three-year period of patient's age 2–17 years. Of the 1700 charts reviewed 823 of these patients received procedural sedation and met the study inclusion criteria. Weight status was classified based on age and gender specific body mass index (BMI) percentiles: underweight, healthy weight, overweight, obese.

Among all weight categories there was no statistical significance, however children with obesity had greater desaturation rates (9.9%) compared with children of underweight, healthy weight, or overweight combined (5.4%), χ² = 4.46, p = 0.035.

The results indicate that children with obesity are almost twice as likely to have a desaturation related to procedural sedation compared with children of other weight status. Providers should be aware that children with obesity may be more likely to desaturate than other children, and therefore be skilled at recognizing this.

5-Hydroxytryptamine 2C (5-HT_2C) receptor is one of the major targets of anti-obesity agents, due to its role in regulation of appetite. In the present study, the 70% EtOH extract of the roots of Bupleurum chinense was revealed to have agonistic activity on 5-HT_2C receptor, and the subsequent bioassay-guided isolation led to identification of several saikosaponins as the active constituents with 5-HT_2C receptor agonistic activity in vitro and anti-obesity activity in vivo. The new compound, 22-oxosaikosaponin d (1), was determined by extensive spectroscopic analyses (HR-ESI-MS, IR, and 1D and 2D NMR). The primary structure-activity relationship study suggested that the intramolecular ether bond between C-13 and C-28 and the number of sugars at C-3 position were closely related to the 5-HT_2C receptor agonistic activity. Saikosaponin a (3), the main saponin in B. chinense, showed obviously agonistic activity on 5-HT_2C receptor with an EC₅₀ value of 21.08 ± 0.33 μmol·L⁻¹ in vitro and could reduce food intake by 39.1% and 69.2%, and weight gain by 13.6% and 16.4%, respectively, at 3.0 and 6.0 mg·kg⁻¹ in vivo. This investigation provided valuable information for the potential use of B. chinense as anti-obesity agent.