Normal weight obesity is associated with metabolic syndrome and insulin resistance in young adults from a middle-income country

Objective: This population-based birth cohort study examined whether normal weight obesity is associated with metabolic disorders in young adults in a middle-income country undergoing rapid nutrition transition. Design and Methods: The sample involved 1,222 males and females from the 1978/79 Ribeira˜o Preto birth cohort, Brazil, aged 23–25 years. NWO was defined as body mass index (BMI) within the normal range (18.5–24.9 kg/m2) and the sum of subscapular and triceps skinfolds above the sex-specific 90th percentiles of the study sample. It was also defined as normal BMI and % BF (body fat) .23% in men and .30% in women. Insulin resistance (IR), insulin sensitivity and secretion were based on the Homeostasis Model Assessment (HOMA) model. Results: In logistic models, after adjusting for age, sex and skin colour, NWO was significantly associated with Metabolic Syndrome (MS) according to the Joint Interim Statement (JIS) definition (Odds Ratio OR = 6.83; 95% Confidence Interval CI 2.84–16.47). NWO was also associated with HOMA2-IR (OR = 3.81; 95%CI 1.57–9.28), low insulin sensitivity (OR = 3.89; 95%CI 2.39–6.33), and high insulin secretion (OR = 2.17; 95%CI 1.24–3.80). Significant associations between NWO and some components of the MS were also detected: high waist circumference (OR = 8.46; 95%CI 5.09–14.04), low High Density Lipoprotein cholesterol (OR = 1.65; 95%CI 1.11–2.47) and high triglyceride levels (OR = 1.93; 95%CI 1.02–3.64). Most estimates changed little after further adjustment for early and adult life variables. Conclusions: NWO was associated with MS and IR, suggesting that clinical assessment of excess body fat in normal-BMI individuals should begin early in life even in middle-income countries

Normal weight obesity is associated with metabolic syndrome and insulin resistance in young adults from a middle-income country.

OBJECTIVE: This population-based birth cohort study examined whether normal weight obesity is associated with metabolic disorders in young adults in a middle-income country undergoing rapid nutrition transition. DESIGN AND METHODS: The sample involved 1,222 males and females from the 1978/79 Ribeirão Preto birth cohort, Brazil, aged 23-25 years. NWO was defined as body mass index (BMI) within the normal range (18.5-24.9 kg/m(2)) and the sum of subscapular and triceps skinfolds above the sex-specific 90th percentiles of the study sample. It was also defined as normal BMI and % BF (body fat) >23% in men and >30% in women. Insulin resistance (IR), insulin sensitivity and secretion were based on the Homeostasis Model Assessment (HOMA) model. RESULTS: In logistic models, after adjusting for age, sex and skin colour, NWO was significantly associated with Metabolic Syndrome (MS) according to the Joint Interim Statement (JIS) definition (Odds Ratio OR = 6.83; 95% Confidence Interval CI 2.84-16.47). NWO was also associated with HOMA2-IR (OR = 3.81; 95%CI 1.57-9.28), low insulin sensitivity (OR = 3.89; 95%CI 2.39-6.33), and high insulin secretion (OR = 2.17; 95%CI 1.24-3.80). Significant associations between NWO and some components of the MS were also detected: high waist circumference (OR = 8.46; 95%CI 5.09-14.04), low High Density Lipoprotein cholesterol (OR = 1.65; 95%CI 1.11-2.47) and high triglyceride levels (OR = 1.93; 95%CI 1.02-3.64). Most estimates changed little after further adjustment for early and adult life variables. CONCLUSIONS: NWO was associated with MS and IR, suggesting that clinical assessment of excess body fat in normal-BMI individuals should begin early in life even in middle-income countries

Associations between normal weight obesity defined as the sum of the triceps and subscapular skinfolds >90^th percentile with metabolic syndrome and its components and insulin resistance, insulin sensitivity and β cell function, 1978/79 Ribeirão Preto birth cohort.

<p>Abbreviations: OR, Odds ratio; CI, Confidence Interval; HOMA, Homeostasis Model Assessment. ^aadjusted for age, sex and skin color. ^badjusted for age, sex, skin colour and early life variables (birth weight, gestational age at birth, maternal schooling, parity, type of delivery and maternal smoking during pregnancy). ^cadjusted for age, sex, skin colour, early and adult life variables (alcohol consumption, family income, schooling, marital status, smoking, percentage of fat in the diet and physical activity). ^dadjusted for age, sex, skin colour, early and adult life variables plus WC. ^eP value calculated by the log-likelihood ratio test. ^fdefined according to the Joint Interim Statement (JIS) of the IDF Task Force on Epidemiology and Prevention, National Heart, Lung and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society and International Association for the Study of Obesity. ^ghigh waist circumference (≥90 cm for men and ≥80 cm for women). ^hlow HDL-cholesterol (<40 mg/dL for men and <50 mg/dL for women). ⁱincreased triglycerides (≥150 mg/dL, use of lipid medications or self-reported diagnosis of hypertriglyceridemia). ^jincreased blood pressure (BP) (systolic pressure ≥130 mmHg and/or diastolic pressure ≥85 mmHg, current usage of antihypertensive drugs or previous diagnosis of hypertension). ^khigh fasting blood glucose (≥100 mg/dL), current use of anti-diabetic medication or previously diagnosed diabetes. ^lBased on the Brazilian Metabolic Syndrome Study - BRAMS criterion (2009) - HOMA2- Insulin resistance >2.8. ^mHOMA2- Insulin sensitivity was considered low if <90th percentile and normal otherwise. ⁿHOMA2- β cell function was considered high if >90th percentile and normal otherwise.</p

Prevalences of metabolic syndrome, its components and insulin resistance by sex among young adults with body mass index within the normal range, 1978/79 Ribeirão Preto birth cohort.

<p>Abbreviations: HDL, High Density Lipoprotein; HOMA, Homeostasis Model Assessment; IR, Insulin Resistance. ^aP value calculated by the chi-square test. ^bdefined according to the Joint Interim Statement (JIS) of the IDF Task Force on Epidemiology and Prevention, National Heart, Lung and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society and International Association for the Study of Obesity. ^cwaist circumference (≥90 cm for men and ≥80 cm for women). ^dincreased triglycerides (≥150 mg/dL, use of lipid medications or self-reported diagnosis of hypertriglyceridemia). ^elow HDL-cholesterol (<40 mg/dL for men and <50 mg/dL for women). ^fincreased blood pressure (BP) (systolic pressure ≥130 mmHg and/or diastolic pressure ≥85 mmHg, current usage of antihypertensive drugs or previous diagnosis of hypertension). ^ghigh fasting blood glucose (≥100 mg/dL), current use of anti-diabetic medication or previously diagnosed diabetes. ^hCut-off point based on the Brazilian Metabolic Syndrome Study - BRAMS criterion (2009). Numbers may not add up to total because of missing values.</p

Normal weight obesity according to early life variables, 1978/79 Ribeirão Preto birth cohort.

a<p>Normal weight obesity defined as a BMI from 18.5 to 24.9 kg/m² and the sum of triceps and subscapular skinfolds >90^th percentile of the study sample for each sex. ^bP values calculated by the chi-square test. ^cValues are mean ± standard deviation. ^dP values calculated by the Student t-test. Numbers may not add up to total because of missing values.</p

Normal weight obesity according to anthropometric and metabolic parameters, 1978/79 Ribeirão Preto birth cohort.

<p>Abbreviations: HOMA, Homeostasis Model Assessment. ^a Normal weight obesity defined as a BMI from 18.5 to 24.9 kg/m² and the sum of triceps and subscapular skinfolds >90^th percentile of the study sample for each sex. ^bValues are mean ± standard deviation. ^cP values calculated by the Student t-test. ^dValues are median (1st quartile – 3rd quartile). ^eP values calculated by the Mann-Whitney non-parametric test.</p

Normal weight obesity according to adult life variables, 1978/79 Ribeirão Preto birth cohort.

a<p>Normal weight obesity defined as a BMI from 18.5 to 24.9 kg/m² and the sum of triceps and subscapular skinfolds >90^th percentile of the study sample for each sex. ^bValues are mean ± standard deviation. ^cP values calculated by the Student t-test. ^dP values calculated by the chi-square test.</p

Associations between normal weight obesity defined as high percent body fat^a with metabolic syndrome and insulin resistance, insulin sensitivity and β cell function, 1978/79 Ribeirão Preto birth cohort.

<p>Abbreviations: OR, Odds ratio; CI, Confidence Interval; HOMA, Homeostasis Model Assessment. ^ahigh percent body fat>23% for males and >30% for females. Percent body fat was estimated based on the Slaughter's equations using the sum of triceps and subscapular skinfolds. ^badjusted for age, sex and skin color. ^cadjusted for age, sex, skin colour and early life variables (birth weight, gestational age at birth, maternal schooling, parity, type of delivery and maternal smoking during pregnancy). ^dadjusted for age, sex, skin colour, early and adult life variables (alcohol consumption, family income, schooling, marital status, smoking, percentage of fat in the diet and physical activity). ^eP value calculated by the log-likelihood ratio test. ^fdefined according to the Joint Interim Statement (JIS) of the IDF Task Force on Epidemiology and Prevention, National Heart, Lung and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society and International Association for the Study of Obesity. ^gBased on the Brazilian Metabolic Syndrome Study - BRAMS criterion (2009) - HOMA2- Insulin resistance >2.8. ^hHOMA2- Insulin sensitivity was considered to be low if <90th percentile and normal otherwise. ⁱHOMA2- β cell function was considered high if >90th percentile and normal otherwise.</p