body mass index

Importance: Obesity affects approximately 21% of US adolescents and is associated with insulin resistance, hypertension, dyslipidemia, sleep disorders, depression, and musculoskeletal problems. Obesity during adolescence has also been associated with an increased risk of mortality from cardiovascular disease and type 2 diabetes in adulthood.

Observations: Obesity in adolescents aged 12 to younger than 18 years is commonly defined as a body mass index (BMI) at the 95th or greater age- and sex-adjusted percentile. Comprehensive treatment in adolescents includes lifestyle modification therapy, pharmacotherapy, and metabolic and bariatric surgery. Lifestyle modification therapy, which includes dietary, physical activity, and behavioral counseling, is first-line treatment; as monotherapy, lifestyle modification requires more than 26 contact hours over 1 year to elicit approximately 3% mean BMI reduction. Newer antiobesity medications, such as liraglutide, semaglutide, and phentermine/topiramate, in combination with lifestyle modification therapy, can reduce mean BMI by approximately 5% to 17% at 1 year of treatment. Adverse effects vary, but severe adverse events from these newer antiobesity medications are rare. Surgery (Roux-en-Y gastric bypass and vertical sleeve gastrectomy) for severe adolescent obesity (BMI ≥120% of the 95th percentile) reduces mean BMI by approximately 30% at 1 year. Minor and major perioperative complications, such as reoperation and hospital readmission for dehydration, are experienced by approximately 15% and 8% of patients, respectively. Determining the long-term durability of all obesity treatments warrants future research.

Conclusions and relevance: The prevalence of adolescent obesity is approximately 21% in the US. Treatment options for adolescents with obesity include lifestyle modification therapy, pharmacotherapy, and metabolic and bariatric surgery. Intensive lifestyle modification therapy reduces BMI by approximately 3% while pharmacotherapy added to lifestyle modification therapy can attain BMI reductions ranging from 5% to 17%. Surgery is the most effective intervention for adolescents with severe obesity and has been shown to achieve BMI reduction of approximately 30%.

Background: Childhood obesity affects 19.3% of children ages 2 to 19 years in the US, and 25.6% of Hispanic children. Study objectives were to (1) assess the feasibility of monitoring physical activity and daily caloric intake in children ages 3 to 6 years, (2) assess whether known obesity risk factors apply to this age-group, and (3) explore the factors that may contribute to the higher prevalence of obesity in Hispanic preschooler.

Methods: Children ages 3 to 6 years were recruited at well child visits (n = 37, 65% male, 30% Hispanic). Parents completed a questionnaire (child’s physical activity and screen time) along with a detailed dietary assessment. Children were provided with a fitness tracker worn for 5 days. Fisher’s exact test, t test/Wilcoxon rank sum tests were conducted.

Results: Thirty-four (92%) participants produced usable activity data. Baseline dietary recall was completed by 35 (97%) of the parents and 25 (68%) completed the second unassisted dietary recall. Mean body mass index of the study sample was 60th percentile, 12 (32%) classified as overweight/obese. Children with overweight/obesity showed no significant difference in mean daily calories compared with those without (1403.9 vs 1406.1 Kcal/day, P = .980) or daily hours of screen time (1.5 ± 1.1 vs 1.7 ± 0.8, P = .442). Children with overweight/obesity had fewer mean daily steps compared with those without overweight/obesity (8038 ± 2685 vs 10038 ± 2599 P = .051).

Discussion: Findings indicate that pedometer activity tracking can be used in children 3 to 6 years old and that decreased physical activity correlates more closely to preschool overweight/obesity than caloric intake.

Objectives The Salt Substitute and Stroke Study (SSaSS) recently reported blood pressure-mediated benefits of a potassium-enriched salt substitute on cardiovascular outcomes and death. This study assessed the effects of salt substitutes on a breadth of outcomes to quantify the consistency of the findings and understand the likely generalisability of the SSaSS results.

Methods We searched PubMed, Embase and the Cochrane Library up to 31 August 2021. Parallel group, step-wedge or cluster randomised controlled trials reporting the effect of salt substitute on blood pressure or clinical outcomes were included. Meta-analyses and metaregressions were used to define the consistency of findings across trials, geographies and patient groups.

Results There were 21 trials and 31 949 participants included, with 19 reporting effects on blood pressure and 5 reporting effects on clinical outcomes. Overall reduction of systolic blood pressure (SBP) was −4.61 mm Hg (95% CI −6.07 to −3.14) and of diastolic blood pressure (DBP) was −1.61 mm Hg (95% CI −2.42 to −0.79). Reductions in blood pressure appeared to be consistent across geographical regions and population subgroups defined by age, sex, history of hypertension, body mass index, baseline blood pressure, baseline 24-hour urinary sodium and baseline 24-hour urinary potassium (all p homogeneity >0.05). Metaregression showed that each 10% lower proportion of sodium choloride in the salt substitute was associated with a −1.53 mm Hg (95% CI −3.02 to −0.03, p=0.045) greater reduction in SBP and a −0.95 mm Hg (95% CI −1.78 to −0.12, p=0.025) greater reduction in DBP. There were clear protective effects of salt substitute on total mortality (risk ratio (RR) 0.89, 95% CI 0.85 to 0.94), cardiovascular mortality (RR 0.87, 95% CI 0. 81 to 0.94) and cardiovascular events (RR 0.89, 95% CI 0.85 to 0.94).

Conclusions The beneficial effects of salt substitutes on blood pressure across geographies and populations were consistent. Blood pressure-mediated protective effects on clinical outcomes are likely to be generalisable across population subgroups and to countries worldwide.

Background: Central obesity is a major manifestation of metabolic syndrome, which is a common health problem in middle-aged and older adults.

Objective: To examine the therapeutic efficacy of tai chi for management of central obesity.

Design: Randomized, controlled, assessor-blinded trial. (ClinicalTrials.gov: NCT03107741).

Setting: A single research site in Hong Kong between 27 February 2016 and 28 February 2019.

Participants: Adults aged 50 years or older with central obesity.

Intervention: 543 participants were randomly assigned in a 1:1:1 ratio to a control group with no exercise intervention (n = 181), conventional exercise consisting of aerobic exercise and strength training (EX group) (n = 181), and a tai chi group (TC group) (n = 181). Interventions lasted 12 weeks.

Measurements: Outcomes were assessed at baseline, week 12, and week 38. The primary outcome was waist circumference (WC). Secondary outcomes were body weight; body mass index; high-density lipoprotein cholesterol (HDL-C), triglyceride, and fasting plasma glucose levels; blood pressure; and incidence of remission of central obesity.

Results: The adjusted mean difference in WC from baseline to week 12 in the control group was 0.8 cm (95% CI, -4.1 to 5.7 cm). Both intervention groups showed reductions in WC relative to control (adjusted mean differences: TC group vs. control, -1.8 cm [CI, -2.3 to -1.4 cm]; P < 0.001; EX group vs. control: -1.3 cm [CI, -1.8 to -0.9 cm]; P < 0.001); both intervention groups also showed reductions in body weight (P < 0.05) and attenuation of the decrease in HDL-C level relative to the control group. The favorable changes in WC and body weight were maintained in both the TC and EX groups, whereas the beneficial effect on HDL-C was only maintained in the TC group at week 38.

Limitations: High attrition and no dietary intervention.

Conclusion: Tai chi is an effective approach to reduce WC in adults with central obesity aged 50 years or older.

Primary funding source: Health and Medical Research Fund.