Associations of overweight with insulin resistance, beta-cell function and inflammatory markers in Chinese adolescents

The relationship of changes in insulin demand and insulin adequacy over the life course

AIMS/HYPOTHESIS

Insulin requirements in the human body undergo continuous changes in response to growth and development. We assessed the life course relationships between insulin demand and insulin adequacy.

METHODS

Three independent Chinese cohorts (204 children, aged [mean ± SD] 7.0 ± 0.5 years; 214 adolescents, aged 15.0 ± 1.8 years; 605 adults, aged 41.5 ± 9.3 years), recruited between 1998 and 2013, underwent OGTT tests. Indices of insulin sensitivity and insulin secretion were calculated based on paired glucose/insulin values during fasting, early phase and late phase of OGTT. Insulin demand and insulin adequacy were calculated by standardised major axis (SMA) regression from the paired insulin sensitivity and secretion indices. We derived the natural logarithm of ratio between the exponential functions of insulin adequacy and insulin demand (RAD) index for further evaluating the relationship between insulin demand and adequacy. The risk of abnormal glucose tolerance (AGT) was evaluated by logistic regression analyses. Area under the receiver-operating characteristic curve (AUC-ROC) analyses, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices were used to demonstrate the discriminative value of the RAD method model.

RESULTS

Adolescents had the lowest insulin sensitivity and the highest insulin secretion in all phases (fasting, early and late phase) of the OGTT, as compared with children and adults in each phase (all p<0.001). Adolescents had the highest insulin demand in all phases and lowest insulin adequacy in the fasting phase (p<0.001). In general, adults had the lowest insulin adequacy in both the early phase (p>0.05) and late phase (p<0.001) of the OGTT. Adolescents had negative RAD values irrespective of overweight and obesity, while, in general, children and adults had positive RAD values (p<0.001 between age groups in each of the fasting, early and late phases of the OGTT). Participants with RAD values below the 25th percentile had a higher risk of AGT compared with those above the 25th percentile (fasting-phase OR 1.86 [95% CI 1.18, 2.91]; early-phase OR 1.99 [95% CI 1.24, 3.19]; late-phase OR 2.49 [95% CI 1.57, 3.97]). The late-phase RAD index had the best performance in evaluating the risk of AGT compared with the fasting- and early-phase RAD indices (late-phase AUC-ROC = 0.635 [95% CI 0.583, 0.687]; late-phase NRI = 0.350 [95% CI 0.190, 0.510]; late-phase IDI = 0.033 [95% CI 0.015, 0.050]).

CONCLUSIONS/INTERPRETATION

The relationship between insulin demand and insulin adequacy changed throughout the life course. Adolescents had an imbalanced relationship between insulin demand and insulin adequacy, while, in general, children and adults had a balanced relationship. RAD is a novel index that was used to efficiently describe this relationship and evaluate the risk of AGT.

Prevalence of overweight/obesity, and associated factors among adolescents aged 12 ∼ 15 in Shandong Province, China: A cross-sectional study

Overweight/obesity among adolescents in Shandong Province, China, has been rising, posing significant public health challenge. Comprehensive investigation is needed to develop effective interventions. Following the Strengthening the Reporting of Observational Studies in Epidemiology guidelines, a stratified random cluster sampling approach was used from September to October 2023 across 17 cities in Shandong Province. The study included 165 middle schools, surveying 99,638 students aged 12 ∼ 15. After applying exclusion criteria, 97,356 students (97.71% effective rate) completed anthropometric measurements and questionnaires. Overweight/obesity were assessed based on national and international standards. Univariable chi-square test and multivariable logistic regression were used to analyze factors influencing overweight/obesity. In 2023, the overweight/obesity rate among 12 ∼ 15-year-olds in Shandong was 19.75%. Significant factors included sex, age, residence, family income, parental weight status and activity, mother's gestational diabetes history, birth weight, physical activity, sleep, screen time, homework, and diet. Girls, older adolescents, and those with physically active parents or who themselves engaged in over 1.5 h of daily physical activity had lower odds of being overweight/obese. Adequate sleep and frequent consumption of vegetable and fruit were also protective. Higher odds were associated with urban residence, high family income, overweight/obese parents, maternal gestational diabetes, high birth weight, excessive screen time, extensive homework, and frequent fast food consumption. Overweight/obesity in Shandong adolescents is influenced by multiple determinants. Holistic interventions addressing genetic, behavioral, and environmental factors are essential for promoting healthier lifestyles and reducing the prevalence in this demographic.

Short-term lifestyle education on obesity reduction in adolescents

Backgrounds

Obesity is increasing in adolescents in China. However, the awareness of obesity and prevention on related risk factors were not well known. We aim to assess the effectiveness of short-term health education intervention on obesity in Chinese adolescents.

Methods

In this study, 42 primary and secondary schools from Qingdao were randomly divided into the education and control groups. A total of 11,739 adolescents was included in the current study. The logistic regression was employed to assess odds ratio (OR) of education intervention on overweight and obesity prevalence adjusting for covariates.

Results

The baseline prevalence of overweight and obesity was significantly higher in urban than in rural areas and in boys than in girls. After 1 year lifestyle intervention, the proportion of students with awareness of obesity was higher, meanwhile age-adjusted mean values of weight, body mass index, duration of watching TV and doing homework were lower in education group than control group. The corresponding figures were 43.6 [95% CI (confidence intervals); 43.3-43.9] kg versus 44.3 (95% CI; 44.0-44.6) kg, 18.6 (95% CI; 18.5-18.7) kg/m2 versus 18.9 (95% CI; 18.8-19.1) kg/m2, 1.3 (95% CI; 1.2-1.3) hours/d versus 1.4 (95% CI; 1.3-1.4) hours/d, and 1.5 (95% CI; 1.4-1.5) hours/d versus 1.8 (95% CI, 1.7-1.8) hours/d. The multivariable adjusted OR for combined prevalence of overweight and obesity was 0.85 (95% CI, 0.76-0.96) in education group as compared with control group.

Conclusion

Short-term health education intervention results in significantly higher reductions in obesity parameters and improvement in awareness in Chinese adolescents.

Increased TG Levels and HOMA-IR Score Are Associated With a High Risk of Prediabetes: A Prospective Study

This study aimed to determine the association of blood lipid and insulin levels with the development of prediabetes. In this prospective cohort study, we collected and analyzed data related to demographic characteristics, lipid profiles, and insulin parameters at baseline (2008-2012) and at follow-up (2019-2020). A total of 1205 participants were included. The study found that maintained or elevated Homeostatic Model Assessment for Insulin Resistance (HOMO-IR) score and elevated triglyceride (TG) levels from baseline to follow-up were associated with an increased risk of prediabetes. However, the interaction between blood lipids and insulin had no significant effect on the risk of prediabetes. Our findings indicate that elevated TG or HOMA-IR levels are associated with an increased risk of prediabetes. These findings emphasize the need to formulate initiatives that can help reduce dyslipidemia to prevent the onset of prediabetes and diabetes.

Detecting people at high risk of type 2 diabetes- How do we find them and who should be treated?

Diabetes is a chronic disease characterized by its silent and progressive nature. The prevalence of type 2 diabetes (T2DM) increases with age but with a worrying trend of increasingly young age of diagnosis. Compared to their counterparts with late onset of disease, these younger subjects face long disease duration with increased risk of diabetes-related complications. Besides, there is marked phenotypic heterogeneity which can interact with different interventions to give rise to variable clinical outcomes. Recognized at-risk groups include those with known atherosclerosis and vascular disease, genetic background (family history and non-White ethnic groups), phenotypes of insulin resistance (obesity, metabolic syndrome, women with gestational diabetes or polycystic ovarian syndrome, and men with androgen deficiency) and "pre-diabetes" (impaired glucose tolerance and impaired fasting glucose). These risk factors interact to amplify the risk for diabetes, thus emphasizing the importance of comprehensive assessment. Raising awareness and health literacy, regular screening of high risk subjects, structured lifestyle modification program including early use of pharmacological agents, targeting at predominant pathophysiological defects offers a personalized approach to prevent this global hazard.

A randomized controlled trial to investigate the impact of a low glycemic index (GI) diet on body mass index in obese adolescents

BACKGROUND

The role of a low glycemic index (GI) diet in the management of adolescent obesity remains controversial. In this study, we aim to evaluate the impact of low GI diet versus a conventional Chinese diet on the body mass index (BMI) and other obesity indices of obese adolescents.

METHODS

Obese adolescents aged 15-18 years were identified from population-recruited, territory-wide surveys. Obesity was defined as BMI ≥95th percentile of Hong Kong local age- and sex-specific references. Eligible subjects were randomized to either an intervention with low GI diet (consisting of 45-50% carbohydrate, 30-35% fat and 15-20% protein) or conventional Chinese diet as control (consisting of 55-60% carbohydrate, 25-30% fat and 10-15% protein). We used random intercept mixed effects model to compare the differential changes across the time points from baseline to month 6 between the 2 groups.

RESULTS

104 obese adolescents were recruited (52 in low GI group and 52 in control group; 43.3% boys). Mean age was 16.7 ± 1.0 years and 16.8 ±1.0 years in low GI and control group respectively. 58.7% subjects completed the study at 6 months (65.4% in low GI group and 51.9% in control group). After adjustment for age and sex, subjects in the low GI group had a significantly greater reduction in obesity indices including BMI, body weight and waist circumference (WC) compared to subjects in the control group (all p <0.05). After further adjustment for physical activity levels, WC was found to be significantly lower in the low GI group compared to the conventional group (p = 0.018).

CONCLUSION

Low GI diet in the context of a comprehensive lifestyle modification program may be an alternative to conventional diet in the management of obese adolescents.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Ref. No: NCT01278563.

Obesity and C-reactive protein in various populations: a systematic review and meta-analysis

Obesity has been associated with elevated levels of C-reactive protein (CRP), a marker of inflammation and predictor of cardiovascular risk. The objective of this systematic review and meta-analysis was to estimate the associations between obesity and CRP according to sex, ethnicity and age. MEDLINE and EMBASE databases were searched through October 2011. Data from 51 cross-sectional studies that used body mass index (BMI), waist circumference (WC) or waist-to-hip ratio (WHR) as measure of obesity were independently extracted by two reviewers and aggregated using random-effects models. The Pearson correlation (r) for BMI and ln(CRP) was 0.36 (95% confidence interval [CI], 0.30-0.42) in adults and 0.37 (CI, 0.31-0.43) in children. In adults, r for BMI and ln(CRP) was greater in women than men by 0.24 (CI, 0.09-0.37), and greater in North Americans/Europeans than Asians by 0.15 (CI, 0-0.28), on average. In North American/European children, the sex difference in r for BMI and ln(CRP) was 0.01 (CI, -0.08 to 0.06). Although limited to anthropometric measures, we found similar results when WC and WHR were used in the analyses. Obesity is associated with elevated levels of CRP and the association is stronger in women and North Americans/Europeans. The sex difference only emerges in adulthood.

Role of low-glycemic index diet in management of childhood obesity

Conventional dietary recommendation for obesity management is a low-fat energy-restricted diet, which however, only have modest and non-sustained effects on weight reduction. Alternative dietary interventions, including low-glycemic index (GI) diet, have been proposed. Glycemic index is a measure of blood glucose excursion per unit of carbohydrate. Foods with high GI are rapidly digested, absorbed and transformed into glucose. These processes cause accelerated and transient surges in blood glucose and insulin, earlier return of hunger sensation and excessive caloric intake. Conversely, low-GI diet decreases blood glucose and insulin excursion, promotes greater fat oxidation, decreases lipogenesis and increases satiety. Modern food-processing technology has produced many food products with high GI which may contribute to the burgeoning epidemic of obesity especially in children/adolescents. Epidemiological and clinical trials suggest a role for low-GI diet in the management of childhood obesity and associated cardio-metabolic risks although results are not always consistent. In this article, we shall review the physiological basis and current evidence for and against low-GI diet in obesity management, with particular focus in children and adolescents.

Medical consequences of childhood obesity: a Hong Kong perspective

Childhood obesity is a global epidemic and is associated with medical consequences. These consequences of childhood obesity include its association with cardiovascular risk factors, notably impaired glucose tolerance, hypertension, atherogenic dyslipidemia, micro inflammation, and comorbidities including nonalcoholic fatty liver disease (NAFLD), sleep apnoea, and early atherosclerosis. This article aims to demonstrate and review the local clinical evidences in Hong Kong Chinese children and adolescents in exploring the epidemiology and medical consequences associated with obesity in the youth population and highlighting the research direction in searching the etiology of these associations.

Adiposity is inversely related to insulin sensitivity in relatively lean Chinese adolescents: a population-based twin study

BACKGROUND

Adolescence is a critical period for rising adiposity and falling insulin sensitivity (IS), but the independent relation between adiposity and IS remains understudied.

OBJECTIVE

The objective was to examine which adiposity measures are most strongly associated with IS in nondiabetic adolescents, whether sex-difference exists, and to what degree genetic or environmental factors affect the adiposity-IS relation.

DESIGN

The study included 1613 rural Chinese adolescents (888 males) aged 13-20 y from a population-based twin cohort. We used graphic plots and linear mixed models to examine the relation of anthropometric and dual-energy X-ray absorptiometry-based measures of adiposity with IS [QUantitative Insulin-sensitivity ChecK Index (QUICKI), fasting serum insulin (FSI), homeostasis model assessment of insulin resistance (HOMA-IR)] and structural equation models to estimate genetic/environmental influences on these associations.

RESULTS

In graphic analyses, participants in the highest quintile (quintile 5) of waist circumference (WC) and percentage body fat (%BF) had the lowest QUICKI and the highest FSI and HOMA-IR values for all age-sex groups. In regression models adjusted for age, Tanner stage, zygosity, and physical activity, all adiposity measures showed inverse associations with IS in both sexes, but WC explained the largest fraction of variance in IS measures (10-14%). Of the phenotypic correlations between adiposity measures and IS (-0.28 to -0.38), 74-85% were attributed to shared genetic factors and 15-26% to common unique environmental factors in both sexes.

CONCLUSIONS

In these relatively lean Chinese adolescents, WC and %BF (quintile 5) are the adiposity measures most consistently and strongly associated with decreased IS in both sexes. To a large degree, shared genetic factors contribute to this association.