Fasting insulin level is positively associated with incidence of hypertension among American young adults: a 20-year follow-up study

Chronic Insufficient Sleep in Women Impairs Insulin Sensitivity Independent of Adiposity Changes: Results of a Randomized Trial

OBJECTIVE

Insufficient sleep is associated with type 2 diabetes, yet the causal impact of chronic insufficient sleep on glucose metabolism in women is unknown. We investigated whether prolonged mild sleep restriction (SR), resembling real-world short sleep, impairs glucose metabolism in women.

RESEARCH DESIGN AND METHODS

Women (aged 20-75 years) without cardiometabolic diseases and with actigraphy-confirmed habitual total sleep time (TST) of 7-9 h/night were recruited to participate in this randomized, crossover study with two 6-week phases: maintenance of adequate sleep (AS) and 1.5 h/night SR. Outcomes included plasma glucose and insulin levels, HOMA of insulin resistance (HOMA-IR) values based on fasting blood samples, as well as total area under the curve for glucose and insulin, the Matsuda index, and the disposition index from an oral glucose tolerance test.

RESULTS

Our sample included 38 women (n = 11 postmenopausal women). Values are reported with ±SEM. Linear models adjusted for baseline outcome values demonstrated that TST was reduced by 1.34 ± 0.04 h/night with SR versus AS (P < 0.0001). Fasting insulin (β = 6.8 ± 2.8 pmol/L; P = 0.016) and HOMA-IR (β = 0.30 ± 0.12; P = 0.016) values were increased with SR versus AS, with effects on HOMA-IR more pronounced in postmenopausal women compared with premenopausal women (β = 0.45 ± 0.25 vs. β = 0.27 ± 0.13, respectively; P for interaction = 0.042). Change in adiposity did not mediate the effects of SR on glucose metabolism or change results in the full sample when included as a covariate.

CONCLUSIONS

Curtailing sleep duration to 6.2 h/night, reflecting the median sleep duration of U.S. adults with short sleep, for 6 weeks impairs insulin sensitivity, independent of adiposity. Findings highlight insufficient sleep as a modifiable risk factor for insulin resistance in women to be targeted in diabetes prevention efforts.

Additive interactions between obesity and insulin resistance on hypertension in a Chinese rural population

BACKGROUND

Adiposity and insulin resistance (IR) are closely associated with hypertension; however, the role of interactions between obesity phenotypes and IR in hypertension is unclear. This study aimed to evaluate the interactions of body mass index (BMI), waist circumference (WC), and body fat percentage (BF%) with IR on hypertension risk.

METHODS

We analyzed data from 4888 participants (mean age 57 years, 41.2% men) in the China Northwest Natural Population Cohort, Ningxia Project. BMI, WC, and BF% were determined using bioelectrical impedance analysis devices. IR was estimated using a homeostasis model assessment index (HOMA-IR). Multivariable-adjusted logistic regression was used to evaluate the association between HOMA-IR and hypertension risk. We calculated the relative excess risk and attributable proportion with their 95% confidence intervals (CIs) to assess whether adiposity phenotypes modified the effect of HOMA-IR on hypertension risk.

RESULTS

The crude prevalence of hypertension was 52.2%. The multivariable-adjusted odds ratio of HOMA-IR was 1.80 (95% CI: 1.23-2.65) for the risk of hypertension in the highest versus the lowest quartiles, but this association became marginal in models further adjusting for BMI, WC, and BF% (P for trend = 0.056). Relative excess risk and attributable proportion for interaction between high HOMA-IR and high BF% were 0.32 (0.04-0.59) and 0.33 (0.06-0.60), respectively. Additionally, high truncal and leg BF% and high HOMA-IR accounted for the hypertension risk in women, but not in men. We did not observe any significant interactions between BMI or WC and HOMA-IR on hypertension.

CONCLUSION

BF% modified the association between IR and increased risk of hypertension in women with high truncal and leg BF%, but not in men.

High triglyceride glucose-body mass index correlates with prehypertension and hypertension in east Asian populations: A population-based retrospective study

Background

There is compelling evidence for an association between triglyceride glucose-body mass index (TyG-BMI) and cardiovascular disease (CVD). However, data on the relationship between TyG-BMI and prehypertension (pre-HTN) or hypertension (HTN) remains scant. The aim of this study was to characterize the association between TyG-BMI and pre-HTN or HTN risk, and to assess the ability of TyG-BMI in predicting pre-HTN and HTN in Chinese and Japanese populations.

Methods

A total of 214,493 participants were included in this study. The participants were divided into 5 groups based on quintiles of TyG-BMI index at baseline (Q1, Q2, Q3 Q4 and Q5). Logistic regression analysis was then employed to assess the relationship between TyG-BMI quintiles and pre-HTN or HTN. Results were presented as odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Our restricted cubic spline analysis showed that TyG-BMI was linearly correlated with both pre-HTN and HTN. Multivariate logistic regression analysis indicated that TyG-BMI was independently correlated with pre-HTN [ORs and 95% CIs were 1.011 (1.011-1.012), 1.021 (1.02-1.023), 1.012 (1.012-1.012), respectively] and HTN [ORs and 95% CIs were 1.021 (1.02-1.021), 1.031 (1.028-1.033), 1.021 (1.02-1.021), respectively] in Chinese or Japanese individuals or both groups after adjusting for all variates. In addition, subgroup analyses showed that the relationship between TyG-BMI and pre-HTN or HTN was independent of age, sex, BMI, country, smoking and drinking status. Across all study populations, the areas under the TyG-BMI curve predicting pre-HTN and HTN were 0.667 and 0.762, respectively, resulting in cut-off values of 189.7 and 193.7, respectively.

Conclusion

Our analyses showed that TyG-BMI was independently correlated with both pre-HTN and HTN. Besides, TyG-BMI showed superior predictive power in predicting pre-HTN and HTN compared to TyG or BMI alone.

HOMA-IR as a predictor of Health Outcomes in Patients with Metabolic Risk Factors: A Systematic Review and Meta-analysis

INTRODUCTION

There exists clinical interest in the following question: Is there an association between HOMA-IR and the risk of developing metabolic diseases?

AIMS

Assessing the association between high values of HOMA-IR with the incidence of T2DM, MACE, essential hypertension, dyslipidemia, NASH, and cancer in healthy participants and participants with a component of metabolic syndrome.

METHODS

Databases were searched by an experienced librarian to find eligible studies. Observational cohort studies enrolling healthy adults and adults with metabolic syndrome components that evaluated HOMA as a marker of IR were considered for inclusion. Eligibility assessment, data extraction and risk of bias assessment were performed independently and in duplicate. Baseline characteristics of patients, cutoff values of HOMA-IR to predict metabolic events were extracted independently and in duplicate.

RESULTS

38 studies (215,878 participants) proved eligible. A higher HOMA-IR value had a significant effect on the risk of developing T2DM (HR 1.87; CI 1.40-2.49), presenting non-fatal MACE (HR 1.46; CI 1.08-1.97) and hypertension (HR 1.35; CI 1.15-1.59). No association was found regarding cancer mortality and fatal MACE with higher HOMA-IR values, there was not enough information to carry out a meta-analysis to establish an association between higher values of HOMA with cancer incidence, dyslipidemia, and NASH.

CONCLUSIONS

High values of HOMA were associated with an increased risk of diabetes, hypertension, and non-fatal MACE; yet, not for cardiovascular or cancer mortality. More research is needed to determine the value of the HOMA index in metabolic and cardiovascular outcomes.

PROSPERO REGISTRATION NUMBER

CRD42020187645.

Correlation between non-insulin-based insulin resistance indexes and the risk of prehypertension: A cross-sectional study

The authors aimed to characterize the relationships between non-insulin-based insulin resistance (IR) indexes and the risk of prehypertension, and to compare their abilities to identify prehypertension. The authors recruited 3274 adults who did not have hypertension and were not taking hypoglycemic or lipid-lowering medications. The triglyceride-to-high-density lipoprotein-cholesterol ratio (TG/HDL-C), fasting triglyceride and glucose index (TyG), and metabolic score for IR (METS-IR) were calculated. Bivariate Spearman's correlation analysis and multiple logistic analysis were used. The area under the receiver operating characteristic (ROC) curve was used to compare the ability of the three indexes to identify prehypertension. Systolic and diastolic blood pressure (BP) positively correlated with TG/HDL-C (r = .272, P < .001), TyG (r = .286, P < .001), and METS-IR (r = .340, P < .001) in the entire cohort. Multiple logistic analysis showed that the proportion of prehypertension in the third and fourth quartiles of the TG/HDL-C (Q3 vs. Q1: odds ratio (OR) = 1.527, 95% confidence interval (CI): 1.243-1.988; Q4 vs. Q1: OR = 1.580, 95% CI: 1.231-2.028), TyG (Q3 vs. Q1: OR = 1.519, 95% CI: 1.201-1.923; Q4 vs. Q1: OR = 1.658, 95% CI: 1.312-2.614), and METS-IR (Q3 vs. Q1: OR = 1.542, 95% CI: 1.138-2.090; Q4 vs. Q1:OR = 2.216, 95% CI: 1.474-3.331) were significantly higher than in the lowest quartiles. The areas under the curves and 95% CIs for the identification of prehypertension were .647 (.628-.667) for TG/HDL-C, .650 (.631-.669) for TyG, and .683 (.664-.702) for METS-IR, respectively. Thus, non-insulin-based IR indexes (TG/HDL-C, TyG, and METS-IR) are significantly associated with the risk of prehypertension. Furthermore, METS-IR is better able to identify prehypertension than TG/HDL-C and TyG. These non-insulin-based IR indexes might assist with the prevention of hypertension in primary care and areas with limited medical resources.

Isolated systolic hypertension and insulin resistance assessment tools in young and middle-aged Chinese men with normal fasting glucose: a cross-sectional study

The vital role of insulin resistance (IR) in the pathogenesis of isolated systolic hypertension (ISH) has been expounded at the theoretical level. However, research on the correlation between some specific IR indicators and ISH is still rare, especially at different glycemic statuses. We conducted this study to explore the association between three IR indicators and ISH among young and middle-aged adults with normal fasting plasma glucose (NFG). This large cross-sectional study included 8246 young and middle-aged men with NFG and diastolic blood pressure < 90 mmHg. The homeostasis model assessment for IR (HOMA-IR) index, triglyceride glucose (TyG) index, and the metabolic score for IR (METS-IR) were calculated with the corresponding formula. The proportions of ISH among young and middle-aged men were 6.7% and 4.4%, respectively. After fully adjusting, only HOMA-IR rather than TyG and METS-IR was significantly associated with ISH. Moreover, fully adjusted smooth curve fitting showed that the association between HOMA-IR and ISH were approximately linear in both two age groups (P for non-linearity were 0.047 and 0.430 in young and middle-aged men, respectively). Among young and middle-aged men with NFG, using HOMA-IR instead of noninsulin-dependent IR indicators may have advantages in the hierarchical management of ISH. Further longitudinal research may be needed to determine their potential causal relationship.

Insulin resistance, metabolic syndrome, and blood pressure progression among Blacks: the Jackson Heart Study

OBJECTIVE

There is a paucity of data on the relations of insulin resistance with incident blood pressure (BP) changes among Blacks. We investigated the associations of insulin resistance and metabolic syndrome (MetS) with BP progression in a community-based sample of African Americans.

METHODS

We analyzed 1064 participants without hypertension at baseline (2000-2004) who attended at least one follow-up visit in 2005-2008 or 2009-2013. Four insulin resistance indices [fasting insulin, insulin-to-glucose ratio (IGR), homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI)] and MetS (excluding hypertension in the definition) were assessed at baseline. Robust Poisson regression was used to generate risk ratios (RRs) and 95% confidence intervals (CI) for BP progression and incident hypertension.

RESULTS

Over a median of 7 years, 69.6% progressed to a higher BP category and 62.7% developed hypertension. After multivariable adjustment, participants in the highest quartile of HOMA-IR had higher risks of BP progression [RR 1.25 (95% CI 1.09-1.43), Ptrend = 0.004] and hypertension [RR 1.35 (95% CI 1.16-1.58), Ptrend < 0.001] compared with those in the lowest quartile. A similar positive association of insulin resistance with BP outcomes was noted with insulin resistance assessed using IGR, fasting insulin, and QUICKI. MetS was associated with increased risks of BP progression [RR 1.15 (95% CI 1.02-1.30), P = 0.02] and incident hypertension [RR 1.23 [95% CI 1.08-1.41], P = 0.002]. These associations were present across baseline BP categories.

CONCLUSION

Our findings support the notion that higher insulin resistance levels are associated with greater risks of BP progression and incident hypertension among Blacks.

Diet pattern may affect fasting insulin in a large sample of black and white adults

OBJECTIVE

Dietary modification of insulin resistance may be a strategy for reducing chronic disease. For this study, we tested the hypothesis that higher fasting insulin, a marker for insulin resistance, would be related to diet patterns with a high proportion of carbohydrates, those with a high glycemic index, and those characterized by added sugar and processed starches.

STUDY DESIGN

Data were analyzed on 13,528 nondiabetic participants of the REasons for Geographic and Ethnic Differences in Stroke (REGARDS), an observational study of adults aged ≥45 years residing in 1855 counties across the continental USA. Information on habitual diet was collected using the Block 98 Food Frequency Questionnaire. Percent energy from carbohydrate, glycemic index, and glycemic load were determined for each participant, as well as adherence to five established diet patterns. Logistic regression was used to examine associations of baseline diet characteristics with odds for high fasting insulin [quartiles 3 and 4 (median = 98.9 pmol/L) vs. quartile 1], after adjusting for covariates.

RESULT

Greater percent carbohydrate, glycemic index, and glycemic load, and adherence to sweets/fat and southern diet patterns, was associated with greater odds for high insulin (P for trend <0.05 to <0.0001), whereas adherence to the plant-based and alcohol/salad patterns was associated with lower odds for high insulin (P for linear trend <0.0001).

CONCLUSION

In conclusion, diet pattern is associated with fasting insulin. Future studies are needed to determine if diet interventions designed to lower insulin, perhaps based on the patterns identified in this study, can improve risk for chronic disease.

Long-term glycemic control and prevention of diabetes complications in vivo using oleic acid-grafted-chitosan‑zinc-insulin complexes incorporated in thermosensitive copolymer

Daily injections for basal insulin therapy are far from ideal resulting in hypo/hyperglycemic episodes associated with fatal complications in type-1 diabetes patients. Here we report a delivery system that provides controlled release of insulin closely mimicking physiological basal insulin requirement for an extended period following a single subcutaneous injection. Stability of insulin was significantly improved by formation of zinc-insulin hexamers, further stabilized by electrostatic complex formation with chitosan polymer. Insulin complexes were homogenously incorporated into PLA-PEG-PLA, a biodegradable thermogel copolymer, that instantaneously forms a subcutaneous gel-depot following injection. Chitosan polymer was hydrophobically modified using oleic acid prior to complex formation with insulin to enable distribution of oleic acid-grafted-chitosan‑zinc-insulin complexes into the hydrophobic core of PLA-PEG-PLA thermogel-copolymer micelles. In vivo, daily administration of marketed long-acting insulin, glargine, resulted in fluctuating blood glucose levels between 91 and 443 mg/dL in type 1 diabetic rats. However, single administration of thermogel copolymeric formulation successfully demonstrated slow diffusion of insulin complexes maintaining peak-free basal insulin level of 21 mU/L for 91 days. Sustained release of basal insulin also correlated with efficient glycemic control (blood glucose <120 mg/dL), prevention of diabetic ketoacidosis and absence of cataract development, unlike other treatment groups. Moreover, there was no sign of inflammation, tissue damage, or collagen deposition around depot site, suggesting exceptional biocompatibility of the formulation for long-term use.

Prevalence of potential modifiable factors of hypertension in patients with difficult-to-control hypertension

BACKGROUND

A comprehensive diagnostic evaluation of potential modifiable factors of difficult-to-control hypertension would enable clinicians to target-specific amendable causes. Therefore, we assessed the prevalence of underlying medical conditions, lifestyle factors, and concomitant medication use in an integrated diagnostic evaluation in patients with difficult-to-control hypertension, referred to a tertiary center.

METHODS

The study population consisted of 653 patients referred between 2006 and 2016 for difficult-to-control hypertension to the University Medical Center Utrecht. Difficult-to-control hypertension was defined by not reaching blood pressure (BP) goals despite BP-lowering drug use, or high office BP (>160/100 mmHg) without BP-lowering drug use. Patients were evaluated according to a highly standardized protocol including 24-h ambulatory blood measurements after cessation of BP-lowering drugs, 24-h urine sample, and a isotonic (0.9%) saline infusion test.

RESULTS

In 621 patients (95%) one or more modifiable factors related to hypertension were identified (mean 2.1, SD 1.1). Obesity-related insulin resistance was the most common underlying medical condition which was diagnosed in 130 patients (20%). Primary aldosteronism was diagnosed in 40 patients (6%) and obstructive sleep apnea in 17 patients (3%). Sodium intake was deemed to high (urinary excretion of >6 g/day) in 433 patients (66%). In total, 283 patients (43%) were physical inactive (<30 min/day, during 5 days/week). Oral contraceptive-related hypertension was diagnosed in 10 women (3% of women).

CONCLUSION

In patients with difficult-to-control hypertension there is a high prevalence of potential modifiable factors related to hypertension, highlighting the importance for an integrated diagnostic evaluation.

Impact of 3-year changes in fasting insulin and insulin resistance indices on incident hypertension: Tehran lipid and glucose study

Background

To examine the association between changes in fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and insulin-glucose ratio (IGR) levels, over approximately 3 years with incident hypertension.

Methods

A total of 2814 Iranian participants (1123 men) without hypertension and known diabetes at baseline and the first examination were followed for a median of 6.32 years. The associations between quartiles of changes in fasting insulin and IR indices with incident hypertension were assessed using multivariate Cox proportional hazard regression analyses with first quartile as reference. The models were adjusted for baseline values of insulin or each IR index, and age, sex, smoking, physical activity, educational levels, marital status, history of cardiovascular diseases, baseline levels of systolic and diastolic blood pressures, estimated glomerular filtration rate, triglycerides, total cholesterol, high-density lipoprotein cholesterol, fasting plasma glucose (only for insulin change) and both body mass index (BMI) per se, and its change. Akaike's information criteria (AIC) was applied as indicator for goodness of fit of each predictive model. The discrimination ability of models was calculated using the Harrell's C statistic.

Results

During the study, 594 incident cases of hypertension (253 men) were identified. The 4th quartile of changes in insulin, HOMA-IR, and IGR showed hazard ratios (95% confidence interval) of 1.31 (1.01-1.69), 1.18 (0.92-1.52), and 1.53 (1.18-1.98) for hypertension, respectively, in fully-adjusted models. Changes in fasting insulin levels and IR indices showed significant increasing trends for incident hypertension, moving from 1st to 4th quartiles (all P-values < 0.05). Focusing on model fitness, no superiority was found between changes in fasting insulin, HOMA-IR, and IGR to predict incident hypertension. The discriminatory powers of changes in fasting insulin and IR indices as assessed by C index were similar (i.e. about 80%).

Conclusion

Changes in fasting insulin and IR indices were significantly associated with developing hypertension among normotensive population even after considering BMI changes.

METS-IR, a novel simple insulin resistance indexes, is associated with hypertension in normal-weight Chinese adults

Insulin resistance (IR) plays a crucial role in the development of hypertension, so early recognition of IR is of substantial clinical importance for the management of hypertension. But traditional IR indexes are invasive, complex, and impractical. We aimed to evaluate the associations between three simple IR indexes and hypertension in different body mass index (BMI) categories. A total of 142 005 adults who did not take antihypertensive medication were included in this analysis. The ratio of triglycerides to high-density lipoprotein cholesterol (TG/HDLc), the product of fasting triglycerides and glucose (TyG), and metabolic score for IR (METS-IR) were calculated according to the corresponding formulas. The associations between them and hypertension were analyzed by logistic regression. Among the three indicators, only METS-IR had positive correlations with blood pressure levels (all P < 0.001). After full adjustment, METS-IR was significantly associated with hypertension in the normal BMI group but not in the elevated BMI group. The OR for hypertension in the normal BMI group in the highest quartile of METS-IR was 2.884 (95% CI: 2.468-3.369) in the total sample, 1.915 (95% CI: 1.614-2.271) in females and 2.083 (95% CI: 1.717-2.527) in males. Our findings indicate that METS-IR, a simple and cost-effective IR index, was strongly associated with hypertension in normal-weight Chinese subjects. It could help monitor and manage hypertension in normal-weight individuals.

Sex specific impact of different obesity phenotypes on the risk of incident hypertension: Tehran lipid and glucose study

Background

To investigate the association between different obesity phenotypes and the risk of incident hypertension among both genders.

Methods

The study population included 3659 Iranians (men = 1540), aged ≥20 years free of hypertension at baseline. Participants were classified into six categories of body mass index (BMI)-metabolic health status, in which unhealthy metabolic status was defined based on the presence of > 1 component of metabolic syndrome (MetS) using the joint interim statement (JIS) criteria or the presence of insulin resistance (IR). The association between different obesity phenotypes and incident hypertension was assessed using multivariate Cox's proportional hazard models adjusted for age, current smoking, low physical activity, diabetes mellitus, family history of premature cardiovascular disease, estimated glomerular filtration rate, phase of recruitment, BMI and systolic blood pressure, considering metabolically healthy normal weight group as the reference.

Results

After a median follow-up of 11.6 years 1122 participants (men = 493) experienced hypertension. Using JIS criteria, a significant higher risk of hypertension was observed among metabolically healthy obese and well as metabolically unhealthy groups among men in the age adjusted model; however, a significant higher risk in the fully adjusted model was seen among women in the metabolically healthy obese [hazard ratio (HR) 95% confidence interval (CI) 1.96(1.16-3.32)] as well as metabolically unhealthy normal weight [1.98(1.37-2.86)], overweight [2.08(1.49-2.90)] and obese [2.06(1.27-3.30)] groups. Using insulin sensitive normal weight group as the reference, among men, being overweight or obese with and without IR was significant predictors of incident hypertension in the age adjusted model; however, among women, insulin resistant overweight [1.46(1.06-2.02)] and obese groups, [1.63(1.01-2.62)] showed significant risk in the fully adjusted model.

Conclusion

We concluded that first, there was significant difference between genders in the associations between obesity phenotypes and incident hypertension. Second, in general, metabolic status defined by MetS components as compared to IR could do better in identifying high risk women for hypertension. Third, women populations who are metabolically healthy obese using MetS definition or those with either > 1 component of metabolic syndrome or overweight/obese ones with IR should be prioritized for implementing urgent preventive strategies against hypertension focusing on lifestyle changes.

Where are they now? Retention strategies over 25 years in the Coronary Artery Risk Development in Young Adults (CARDIA) Study

Purpose

In 1991, we described the recruitment and goals for a cohort of young adults. At the time, little was known about long-term retention of young, healthy and mobile adults or minorities. We present retention strategies and rates over 25 years, and predictors of participation at the year 25 follow-up examination of the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a longitudinal investigation of coronary artery disease risk factors in a biracial population initially ages 18-30 years recruited from four U.S. centers in 1985.

Methods

CARDIA has employed a range of strategies to enhance retention, including two contacts per year, multiple tracking methods to locate participants lost-to-follow-up, use of birthday and holiday cards, participant newsletters, examination scheduling accommodations and monetary reimbursements, and a standing committee whose primary purpose has been to continually review retention rates and strategies and identify problems and successes.

Results

For 25 years, CARDIA has maintained >90% contact with participants between examinations, over 80% at any 2-year interval, and a 72% 25-year examination attendance rate. Baseline predictors of year 25 examination attendance include white race, female sex, older age, higher education, nonsmoking and moderate alcohol consumption.

Conclusion

Consistent use of multiple retention strategies, including attention to contact rates and sharing of best strategies across study centers, has resulted in high retention of a diverse, initially young, biracial cohort.

Fasting insulin, insulin resistance and risk of hypertension in the general population: A meta-analysis

BACKGROUND

Studies on the association of fasting insulin concentrations or insulin resistance with subsequent risk of hypertension have yielded conflicting results.

OBJECTIVE

To quantitatively assess the association of fasting insulin concentrations or homeostasis model assessment insulin resistance (HOMA-IR) with incident hypertension in a general population by performing a meta-analysis.

METHODS

We searched the PubMed and Embase databases until August 31, 2016 for prospective observational studies investigating the elevated fasting insulin concentrations or HOMA-IR with subsequent risk of hypertension in the general population. Pooled risk ratio (RR) and 95% confidence interval (CI) of hypertension was calculated for the highest versus the lowest category of fasting insulin or HOMA-IR.

RESULTS

Eleven studies involving 10,230 hypertension cases were identified from 55,059 participants. Meta-analysis showed that the pooled adjusted RR of hypertension was 1.54 (95% CI 1.34-1.76) for fasting insulin concentrations and 1.43 (95% CI 1.27-1.62) for HOMA-IR comparing the highest to the lowest category. Subgroup analysis results showed that the association of fasting insulin concentrations with subsequent risk of hypertension seemed more pronounced in women (RR 2.07; 95% CI 1.19-3.60) than in men (RR 1.48; 95% CI 1.17-1.88).

CONCLUSIONS

This meta-analysis suggests that elevated fasting insulin concentrations or insulin resistance as estimated by homeostasis model assessment is independently associated with an exacerbated risk of hypertension in the general population. Early intervention of hyperinsulinemia or insulin resistance may help clinicians to identify the high risk of hypertensive population.

Hyperinsulinemia is associated with the loss of appendicular skeletal muscle mass at 4.6 year follow-up in older men and women

BACKGROUND & AIMS

Homeostasis model assessment as a marker of insulin resistance has been associated with the pronounced loss of appendicular skeletal muscle mass in older adults. In the present study, we hypothesized that hyperinsulinemia as an early predictor of insulin resistance may be associated with the loss of appendicular skeletal muscle mass (ASM).

METHODS

This is a cohort study that included 147 well-functioning older men and women subjects who were followed for a period of 4.6 ± 1.8 years. Lean tissue in arm and legs, or ASM, was derived from dual-energy X-ray absorptiometry at baseline with follow-up measurements to obtain the relative change. Hyperinsulinemia was defined empirically at the 75th percentile.

RESULTS

The relative change in ASM was negative and significant throughout the quartiles of fasting insulin levels (p ≤ 0.05); however, the loss of ASM was more pronounced in the later quartiles (-0.7 kg) compared with the relative change in Q1 and Q2 (-0.5 kg and -0.3 kg). The unadjusted analysis indicates a significant association between hyperinsulinemia and the loss of ASM (β = -0.28, 95% CI-0.57-0.009, p = 0.05), an association that remained significant after adjusting for several covariates.

CONCLUSION

Hyperinsulinemia as an early marker of insulin resistance was associated with the loss of ASM in a cohort study of community-dwelling older men and women subjects without other chronic health conditions. The use of fasting insulin levels >8.4 μU/mL may help clinicians identify individuals in the geriatric population who are at a high risk of loss of appendicular skeletal muscle mass.

Fasting glucose and HbA1c levels as risk factors for the development of hypertension in Japanese individuals: Toranomon hospital health management center study 16 (TOPICS 16)

We investigated the effect of elevated concentrations of fasting plasma glucose (FPG) or hemoglobin A1c (HbA1c) on the risk of development of hypertension among apparently healthy Japanese. Studied were 9584 individuals without known diabetes and hypertension. During a 5-year follow-up period, 1098 individuals developed hypertension. Elevated concentrations of FPG, rather than of HbA1c, were significantly predictive of future hypertension. Compared with the lowest quartile category of FPG (<4.9 mmol l(-1)), the second (4.9-<5.2 mmol l(-1)), third (5.2-<5.6 mmol l(-1)) and highest (⩾ 5.6 mmol l(-1)) quartile categories had age-, sex- and body mass index-adjusted odds ratios (95% confidence interval) of 1.35 (1.10, 1.66), 1.39 (1.13, 1.71) and 1.85 (1.51, 2.28) for hypertension, respectively. In the highest quartile of FPG, the multivariate-adjusted OR was 1.37 (1.10, 1.70) compared with the lowest quartile. Results of these adjusted models showed no significant association across quartile categories of HbA1c concentrations and an increased risk of developing hypertension. The joint effect of hyperglycemia and overweight, older age or prehypertension resulted in further elevated ORs for hypertension than the absence of such an association. Higher FPG levels rather than HbA1c were strongly predictive of future hypertension among Japanese. Hyperglycemia along with older age, overweight and prehypertension contributed to identifying individuals at increased risk of developing hypertension.

Fasting insulin concentrations and incidence of hypertension, stroke, and coronary heart disease: a meta-analysis of prospective cohort studies

BACKGROUND

Insulin resistance is a precursor of numerous chronic diseases, including cardiovascular disease (CVD). The fasting insulin concentration is considered a reasonable surrogate of insulin resistance, especially among nondiabetic individuals.

OBJECTIVE

We aimed to quantitatively summarize the literature on the association of fasting insulin concentrations with risk of hypertension, stroke, and coronary heart disease (CHD) by conducting a meta-analysis of prospective cohort studies.

DESIGN

Eligible studies were identified by searching PubMed and EMBASE through January 2013. Additional information was retrieved through Google Scholar or a hand review of the reference lists from relevant articles. Prospective cohort studies that reported RRs and corresponding 95% CIs for the association of interest were identified. Data were extracted independently by 2 investigators, and the weighted RRs and 95% CIs for the associations were obtained by using a random-effects model.

RESULTS

Of the 22 identified studies, 10 reported results on hypertension (36,617 individuals and 4491 cases), 7 on stroke (27,887 individuals and 1550 cases), and 9 on CHD (22,379 individuals and 1986 cases). Comparison of the highest with the lowest quantile of fasting insulin concentrations showed a pooled RR (95% CI) of 1.63 (1.35, 1.97) for hypertension, 1.18 (0.87, 1.60) for stroke, and 1.50 (1.28, 1.77) for CHD. Each 50-pmol/L increment in fasting insulin was associated with a 25% increase in risk of hypertension [RR: 1.25 (1.14, 1.36)] and a 16% increase in risk of CHD [RR: 1.16 (1.10, 1.22)] but was not associated with risk of stroke [RR: 0.999 (0.99, 1.01)].

CONCLUSIONS

A higher fasting insulin concentration or hyperinsulinemia was significantly associated with an increased risk of hypertension and CHD but not stroke. This meta-analysis suggests that early fasting insulin ascertainment in the general population may help clinicians identify those who are potentially at high risk of CVD.

Plasma bicarbonate and odds of incident hypertension

BACKGROUND

Several biomarkers of metabolic acidosis, including lower plasma bicarbonate, have been associated with prevalent hypertension in cross-sectional studies. We sought to examine prospectively whether lower plasma bicarbonate is associated with incident hypertension.

METHODS

We conducted a prospective case-control study nested within the Nurses' Health Study II. Plasma bicarbonate was measured in 695 nonobese women without hypertension at time of blood draw who subsequently developed hypertension during 6 years of follow-up. Control subjects were matched to case subjects according to age, race, time and day of blood draw, and day of menstrual cycle. We used unconditional logistic regression to generate odds ratios (ORs) for development of hypertension by quintile of baseline plasma bicarbonate.

RESULTS

After adjusting for matching factors, body mass index, family history of hypertension, plasma creatinine, and dietary and lifestyle factors, higher plasma bicarbonate was associated with lower odds of developing hypertension across quintiles (P for linear trend = 0.04). Those in the highest compared with the lowest quintile of plasma bicarbonate had 31% lower odds of developing hypertension (OR = 0.69; 95% confidence interval = 0.48-0.99). Further adjustment for diet-estimated net endogenous acid production, plasma insulin, 25-hydroxyvitamin D, and uric acid did not alter these findings.

CONCLUSIONS

Our case-control study is consistent with a modest association between higher plasma bicarbonate and reduced odds of developing hypertension among nonobese women, although our findings are of borderline statistical significance. Further research is required to confirm this finding as part of a larger prospective cohort study and to elucidate the mechanism for this relation.

Parental history of type 2 diabetes, TCF7L2 variant and lower insulin secretion are associated with incident hypertension. Data from the DESIR and RISC cohorts

AIMS/HYPOTHESIS

The relationship between insulin secretion and the incidence of hypertension has not been well characterised. We hypothesised that both a parental history of diabetes and TCF7L2 rs7903146 polymorphism, which increases susceptibility to diabetes because of impaired beta cell function, are associated with incident hypertension. In a separate cohort, we assessed whether low insulin secretion is related to incident hypertension.

METHODS

Nine year incident hypertension was studied in 2,391 normotensive participants from the Data from an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) cohort. The relationship between insulin secretion and 3 year incident hypertension was investigated in 1,047 non-diabetic, normotensive individuals from the Relationship between Insulin Sensitivity and Cardiovascular Disease (RISC) cohort. Insulin secretion during OGTT was expressed in relation to the degree of insulin resistance, as assessed by a hyperinsulinaemic-euglycaemic clamp.

RESULTS

In the DESIR cohort, a parental history of diabetes and the TCF7L2 at-risk variant were both associated with hypertension incidence at year 9, independently of waist circumference, BP, fasting glucose, insulin levels and HOMA-IR at inclusion (p = 0.02 for parental history, p = 0.006 for TCF7L2). In the RISC cohort, a lower insulin secretion rate during the OGTT at baseline was associated with both higher BP and a greater risk of hypertension at year 3. This inverse correlation between the insulin secretion rate and incident hypertension persisted after controlling for baseline insulin resistance, glycaemia and BP (p = 0.007).

CONCLUSIONS/INTERPRETATION

Parental history of diabetes, TCF7L2 rs7903146 polymorphism and a reduced insulin secretion rate were consistently associated with incident hypertension. A low insulin secretion rate might be a new risk factor for incident hypertension, beyond insulin resistance.

Associations of insulin resistance with cardiovascular risk factors and inflammatory cytokines in normal-weight Hispanic women

OBJECTIVE

To investigate the associations of markers of insulin resistance with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women.

RESEARCH DESIGN AND METHODS

Seventy-one normal-weight (BMI <25 kg/m(2)) Hispanic women (age, 20-39 years) participated in a fasting blood draw for glucose, insulin, lipids, and inflammatory markers; a glucose tolerance test; anthropometric and blood pressure measurements; body composition by dual-energy x-ray absorptiometry; and measurements of cardiorespiratory fitness via Vo2max and daily physical activity by accelerometer. RESULTS Six percent of participants had impaired fasting glucose, 14% had impaired glucose tolerance, and 48% had at least one cardiovascular disease risk factor. Homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin were positively correlated with glucose, triglycerides, systolic blood pressure, and diastolic blood pressure, and were negatively correlated with adiponectin (P < 0.05). The 2-h insulin was positively correlated with diastolic blood pressure, triglycerides, and high-sensitivity C-reactive protein. HOMA-IR and fasting insulin remained significantly and positively related to glucose, triglycerides, and blood pressure after adjustment for body composition. The relationships between markers of insulin resistance and adiponectin and high-sensitivity C-reactive protein were attenuated after adjustment for body composition.

CONCLUSIONS

Surrogate markers of insulin resistance were associated with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women. Our findings suggest that HOMA-IR, fasting, and 2-h insulin may be important clinical markers for identifying young, normal-weight, Hispanic women who may be at risk for development of type 2 diabetes and cardiovascular disease. Our findings show the importance of early screening for prevention of type 2 diabetes and cardiovascular disease in this population.