Relationship between the metabolic syndrome and the development of hypertension in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2)

Degree of Blood Glucose Control and Risk of Hypertension in Chinese Adults with T2DM: A Cross-Sectional Study

Background

Diabetes mellitus and hypertension often coexist and share common risk factors. This study investigated the correlation between glycemic management and the prevalence of hypertension among Chinese adults diagnosed with type 2 diabetes mellitus (T2DM).

Methods

This study included 1715 patients with T2DM from four cities in Anhui Province, China. Sociodemographic characteristics of the sample participants were collected via questionnaires. A univariate analysis of variance (ANOVA) was utilized for continuous variables, and chi-square testing was used for categorical variables. Binary logistic regression was utilized to examine the relationship between blood pressure and variables including fasting plasma glucose (FPG), glycosylated haemoglobin (HbA1c), body mass index (BMI), waist circumference (WC), physical activity, dyslipidemia, and family history of hypertension.

Results

FPG levels did not increase the risk of hypertension, while HbA1c was significantly and negatively associated with hypertension risk. HbA1c levels ranged from 7.2 to 8.6%, with odds ratios (OR) of 0.68 and 95% confidence intervals (CI) of 0.48 to 0.97 and a significant p value of less than 0.05. For the HbA1c levels above 8.6%, the OR was 0.58 with a 95% CI of 0.39 to 0.87 and a significant p value of less than 0.01. Furthermore, advanced age, higher BMI, greater waist circumference, presence of dyslipidemia, and positive family history of hypertension were all found to be significantly and independently linked to a heightened risk of developing hypertension. These associations remain significant after further adjustment.

Conclusion

There was a negative association between HbA1c and the risk of hypertension, and the association remained significant after adjustment for antihypertensive drug use.

Prevalence of metabolic syndrome in the United States National Health and Nutrition Examination Survey 2011-18

PURPOSE

To estimate the prevalence of metabolic syndrome (MetS) in the US National Health and Nutrition Examination Survey (NHANES) 2011-18.

METHODS

This study included 8183 eligible nonpregnant participants aged ≥20 years from the NHANES 2011-18. MetS was defined as the presence of at least three of the following components: central obesity, reduced high-density lipoprotein cholesterol, elevated triglycerides, elevated blood pressure, and elevated fasting blood glucose. The prevalence of MetS was estimated taking into account the complex sampling. The time trend was evaluated using logistic regression.

RESULTS

The total prevalence of MetS increased from 37.6% [95% confidence interval (CI): 34.0%-41.4%] in 2011-12 to 41.8% (95% CI: 38.1%-45.7%) in 2017-18 (P for trend = .028). Among the MetS components, the prevalence of elevated glucose increased from 48.9% (95% CI: 45.7%-52.5%) in 2011-12 to 64.7% (95% CI: 61.4%-67.9%) in 2017-18 (P for trend <.001). The prevalence of MetS in participants with low educational attainment increased from 44.4% (95% CI: 38.8%-50.1%) in 2011-12 to 55.0% (95% CI: 50.8%-59.1%) in 2017-18 (P for trend = .01).

CONCLUSION

The prevalence of MetS increased during 2011-18, notably in participants with low educational attainment. Lifestyle modification is needed to prevent MetS and the associated risks of diabetes and cardiovascular disease. Key messages What is already known on this topic: Prevalence of metabolic syndrome is an index of the cardiometabolic health of a population. What this study adds: The prevalence of metabolic syndrome in US adults increased during 2011-18, notably in participants with low educational attainment. How this study might affect research, practice, or policy: Lifestyle modification is needed to prevent metabolic syndrome and the associated risks of diabetes and cardiovascular disease.

Comparison of Fasting Insulin Level, Homeostatic Model of Insulin Resistance, and Lipid Levels between Patients with Primary Hypertension and Normotensive Subjects

BACKGROUND

Hyperinsulinemia and insulin resistance occurs in obese patients with primary hypertension independent of diabetes and obesity. This study was aimed at assessing serum fasting insulin levels, the homeostatic model assessment for insulin resistance (HOMA-IR), and serum lipid levels in non-obese patients with primary hypertension when compared to normotensive subjects.

METHODS

This observational study comprised 100 patients over 18 years of age, divided into two groups. The hypertensive group comprised non-obese patients with primary hypertension (n=50); the normotensive group comprised normotensive age- and sex-matched individuals (n=50). Patients with diabetes, impaired fasting glucose, obesity, and other causative factors of insulin resistance were excluded from the study. Serum fasting insulin levels and fasting lipid profiles were measured, and insulin resistance was calculated using HOMA-IR. These data were compared between the two groups. Pearson's correlation coefficient was used to assess the extent of a linear relationship between HOMA-IR and to evaluate the association between HOMA-IR and systolic and diastolic blood pressures.

RESULTS

Mean serum fasting insulin levels (mIU/L), mean HOMA-IR values, and fasting triglyceride levels (mg/dL) were significantly higher in the hypertensive versus normotensive patients (10.32 versus 6.46, P<0.001; 1.35 versus 0.84, P<0.001; 113.70 versus 97.04, P=0.005, respectively). The HOMA-IR levels were associated with systolic blood pressure (r value 0.764, P=0.0005).

CONCLUSION

We observed significantly higher fasting insulin levels, serum triglyceride levels, and HOMA-IR reflecting hyperinsulinemia and possibly an insulin-resistant state among primary hypertension patients with no other causally linked factors for insulin resistance. We observed a significant correlation between systolic blood pressure and HOMA-IR.

Hypertension and psychosis

Hypertension, a prevalent component of metabolic syndrome (MetS), is a well-known risk factor for cardiovascular diseases (CVD). Psychosis is a feature in the schizophrenia spectrum. Meta-analysis suggests that the prevalence of hypertension in schizophrenia and related disorders is 39%. This may be explained by a unidirectional association between hypertension and psychosis, in that psychosis can be a causative factor of hypertension via antipsychotic medication, inflammation and irregular autonomic nervous system activity through multiple mechanisms. Obesity is a side effect of antipsychotic medication and is a risk factor for hypertension. Obesity leads to raised blood pressure, atherosclerosis, increased triglyceride concentration and decreased high-density lipoprotein concentration. Inflammation accompanies hypertension and obesity. In recent years, the role of inflammation in the onset of psychosis has been increasingly recognised. It underlies the immune dysregulation observed in both schizophrenia and bipolar disorder. Interleukin-6, a marker and driver of inflammation, is related to obesity and plays a role in the pathogenesis of MetS and hypertension. The lack of preventive care of hypertension and other MetS risk factors for patients on antipsychotic medication is reflected in the high incidence of CVD in this population. It is important to detect and treat MetS and hypertension in patients with psychosis in order to reduce cardiovascular morbidity and mortality in this population.

A Novel Machine Learning Strategy for the Prediction of Antihypertensive Peptides Derived from Food with High Efficiency

Strategies to screen antihypertensive peptides with high throughput and rapid speed will doubtlessly contribute to the treatment of hypertension. Food-derived antihypertensive peptides can reduce blood pressure without side effects. In the present study, a novel model based on the eXtreme Gradient Boosting (XGBoost) algorithm was developed and compared with the dominating machine learning models. To further reflect on the reliability of the method in a real situation, the optimized XGBoost model was utilized to predict the antihypertensive degree of the k-mer peptides cutting from six key proteins in bovine milk, and the peptide-protein docking technology was introduced to verify the findings. The results showed that the XGBoost model achieved outstanding performance, with an accuracy of 86.50% and area under the receiver operating characteristic curve of 94.11%, which were better than the other models. Using the XGBoost model, the prediction of antihypertensive peptides derived from milk protein was consistent with the peptide-protein docking results, and was more efficient. Our results indicate that using the XGBoost algorithm as a novel auxiliary tool is feasible to screen for antihypertensive peptides derived from food, with high throughput and high efficiency.

A 2020 Vision of Hypertension

Hypertension is a common chronic disease affecting a large section of the general population. Hypertension is highly prevalent in the elderly because blood pressure (BP) rises with age. The risk of developing hypertension increases with predisposing genes, intrauterine growth retardation, prematurity and childhood obesity. BP is easier to control in the young. Non-pharmacological treatment through lifestyle changes, such as weight control and leisure-time physical activity, is more likely to be successful in young people. Hypertension in older adults is more difficult to control, requiring the use of more than one antihypertensive drug. Adverse effects and compliance become problematic. Much research is now directed at novel ways of controlling BP such as denervation. The change in definition of hypertension in the American guideline highlights the need to identify and manage hypertension early, at a stage when it is potentially reversible.

Prevalence of metabolic syndrome among ethnic groups in China

Background

Metabolic syndrome (MetS) is common in China, which has a multi-ethnic population of 1·3 billion. We set out to determine the prevalence of MetS and its components in different ethnic groups.

Methods

This nationwide cross-sectional survey involved 24,796 participants from eight ethnicities in six provinces in China from 2008 to 2011. MetS was defined using the modified National Cholesterol Education Program Adult Treatment Panel III criteria. Results were analysed using SPSS version 22·0 in 2018. Logistic regression was used for deriving odds ratios and 95% confidence intervals of risk factors for the MetS.

Results

The prevalence of MetS increased with age from 3·60% to 21·68%. After age standardization, the prevalence of MetS, in descending order, was 35·42% (Korean), 22·82% (Hui), 19·80% (Han), 13·72% (Miao), 12·90% (Tujia), 12·04% (Li), 11·61% (Mongolian), 6·17% (Tibetan). Korean ethnicity was associated with a higher prevalence in five components of MetS, while Tibetan ethnicity was associated with lower prevalence except decreased HDL cholesterol. Logistic regression analyses showed that age, drinking and being non-Tibetan were associated with a higher risk of MetS.

Conclusions

Within one country, albeit a large one, the prevalence of MetS can vary greatly. Chinese of Korean ethnicity had a much higher prevalence than Tibetan ethnicity. Measures to tackle MetS should be tailored to the ethnic groups within a population.

The relationship between Plasma Markers and Essential Hypertension in Middle-aged and Elderly Chinese Population: A Community Based Cross-sectional Study

Plasma markers have been continuously advocated as pointers to estimate the long-term risk of cardiovascular disease in the general population. We examined the relationship between plasma high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), high-sensitivity cardiac troponin T (hs-cTnT), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), 25-Hydroxyvitamin D (25OHD), glycosylated hemoglobin A1c (HbA1c), and serum uric acid (SUA) levels and hypertension in middle and old aged population. A total of 2624 Chinese (62.02 ± 5.73 years old) were recruited into a population-based, cross-sectional study. Plasma hs-CRP, Hcy, HbA1c, and SUA levels were significantly higher in the hypertension group compared with control in the entire population and men (P = 0.05 for all). We observed a positive association between the highest quartiles of Hcy, NT-proBNP, HBA1c concentrations, and the prevalence of hypertension, OR (95% CI) = 1.48 (1.16–1.90), 1.62 (1.27–2.07) and 1.94 (1.49–2.52), respectively. The multivariable-adjusted OR of hypertension for the fourth versus the first quartile of homocysteine were 2.00 and 1.39 in men and women, respectively. In conclusion, our study found an independent and robust association between elevated Hcy, NT-ProBNP, and HBA1c levels and prevalence of hypertension in the middle-aged and elderly Chinese population. A follow-up study is necessary to endorse the observed association.

FGF21 increases water intake, urine output and blood pressure in rats

Fibroblast growth factor 21 (FGF21) is a hormone secreted by the liver in response to metabolic stress. In addition to its well-characterized effects on energy homeostasis, FGF21 has been shown to increase water intake in animals. In this study, we sought to further explore the effects of FGF21 on fluid homeostasis in rats. A single dose of a long-acting FGF21 analog, PF-05231023, significantly increased water consumption, which was accompanied by an elevation in urine output that appeared prior to a significant change in water intake. We observed that FGF21 rapidly and significantly increased heart rate and blood pressure in telemeter-implanted rats, before changes in urine output and water intake were observed. Our data suggest that sympathetic activation may contribute to the pathogenesis by which FGF21 increases blood pressure as the baroreceptor unloading induced reflex tachycardia was significantly elevated in FGF21-treated animals. However, FGF21 was still capable of causing hypertension in animals in which approximately 40% of the sympathetic post-ganglionic neurons were ablated. Our data suggest that FGF21-induced water intake is in fact secondary to diuresis, which we propose to be a compensatory mechanism engaged to alleviate the acute hypertension caused by FGF21.

Body mass index, abdominal adiposity, weight gain and risk of developing hypertension: a systematic review and dose-response meta-analysis of more than 2.3 million participants

OBJECTIVE

This study aimed to test the association between anthropometric measures and risk of developing hypertension.

METHODS

We did a systematic search using PubMed and Scopus, from inception up to January 2017. Prospective cohort studies reporting the risk estimates of hypertension for three or more quantitative categories of indices of general and abdominal adiposity were included. Summary relative risks were calculated using random-effects models.

RESULTS

Fifty-seven prospective cohort studies were included. Summary relative risks were 1.49 (95% confidence interval [CI]: 1.41, 1.58; I²  = 97.4%, n = 50) for a five-unit increment in body mass index, 1.27 (95%CI: 1.15, 1.39; I²  = 95.0%, n = 14) for a 10-cm increment in waist circumference, 1.16 (95%CI: 1.09, 1.23; I²  = 77.8%, n = 5) for weight gain equal to a one-unit increment in BMI, and 1.37 (95%CI: 1.24, 1.51; I²  = 76.4%, n = 8) and 1.74 (95%CI: 1.35, 2.13; I²  = 58.9%, n = 4) for a 0.1-unit increment in waist-to-hip ratio and waist-to-height ratio, respectively. The risk of hypertension increased continuously with increasing all anthropometric measures, and also along with weight gain.

CONCLUSION

Being as lean as possible within the normal body mass index range may be the best suggestion in relation to primary prevention of hypertension.

The associations of metabolic syndrome with incident hypertension, type 2 diabetes mellitus and chronic kidney disease: a cohort study

PURPOSE

Metabolic syndrome (MetS) has been extensively studied for its long-term health effects, typically through conventional Cox proportional hazards regression modeling of the overall association of MetS with a single outcome. Such an approach neglects the inherent links between MetS-related disease outcomes and fails to provide sufficient insights into the impact of each component of MetS over time.

METHODS

We therefore conducted a retrospective cohort study of 63,680 individuals who received health check-ups at the MJ Health Screening Center in Taiwan from 1997-2005 to study the subsequent risks of hypertension, type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) simultaneously for MetS and its components. Multivariate-adjusted hazard ratios (HRs) were calculated using Cox models for multiple failure outcomes.

RESULTS

At baseline, MetS was identified in 7835 participants. Over a median follow-up of 3 years, 8252, 1634, and 6714 participants developed hypertension, T2DM and CKD, respectively. The HR for MetS was 2.41 (95% CI 2.29-2.53) for hypertension, 5.17 (95% CI 4.68-5.71) for T2DM and 1.22 (95% CI 1.15-1.31) for CKD. Three MetS components showed the strongest association with each of the outcomes: elevated blood pressure with hypertension (HR = 3.62, 95% CI 3.46-3.79), raised fasting plasma glucose with T2DM (HR = 8.89, 95% CI 7.86-10.06) and elevated triglycerides with CKD (HR = 1.14, 95% CI 1.08-1.21).

CONCLUSIONS

MetS may help identify individuals with metabolic profiles that confer incremental risks for multiple diseases. Additionally, several components of the syndrome should be considered by clinicians, as they show stronger associations with specific diseases than MetS.

The Potential Role of Fibroblast Growth Factor 21 in Lipid Metabolism and Hypertension

Fibroblast growth factor (FGF) 21 belongs to the FGF superfamily that is involved in cell proliferation and differentiation, neural development, angiogenesis, and metabolism. FGF21 requires β-Klotho as a co-receptor. Tissues involved in metabolism such as the liver, adipose tissues, skeletal muscle, and pancreas express FGF21. Starvation increases hepatic expression of FGF21, which then acts centrally to increase hepatic gluconeogenesis. FGF21 also increases fatty acid oxidation. This may be relevant in cold exposure, when expression of FGF21 is induced. Chronic treatment with recombinant FGF21 reduces serum and hepatic triglyceride levels and ameliorates fatty liver in obese mice, through the suppression of the lipogenic gene, Srebp-1. FGF21 reduces hepatic cholesterol production by inhibiting Srebp-2, a transactivator of proprotein convertase subtilisin/kexin type 9 (PCSK9). LY2045319, an FGF21 analog, reduces LDL-C and triglycerides and increases HDL-C in obese human subjects with type 2 diabetes. FGF21 does not seem to lower blood pressure acutely. In rats fed with high-fructose water to induce mild hypertension, 4-week treatment with recombinant FGF21 led to normalization of systolic blood pressure and improved serum lipid profile. FGF receptors and β-Klotho are expressed on the nucleus tractus solitarii and nodose ganglion in the baroreflex afferent pathway. Moreover, FGF21 acts on the hypothalamus to release corticosterone and induces in adipocytes the production of adiponectin, an adipokine with antihypertensive activities. Therefore, FGF21 may decrease blood pressure indirectly, through its actions in the liver, brain, and adipose tissues.

Impaired fasting glucose predicts the development of hypertension over 6years in female adults: Results from the rural Chinese cohort study

AIMS

To investigate whether impaired fasting glucose (IFG) is an independent risk factor for incident hypertension in a rural Chinese population.

METHODS

We selected 9583 eligible participants 18 to 75years old, who were without hypertension and diabetes at baseline (from 2007 to 2008) and were from a rural area in the middle of China. Concentration of fasting glucose at baseline was assessed in quartiles to predict hypertension risk by gender. Odds ratios (ORs) and 95% confidence intervals (CIs) for IFG (fasting glucose of 100 to 125mg/dl) associated with hypertension were estimated by logistic regression models.

RESULTS

Risk of hypertension was increased for females with glucose levels in quartile 2 (90-96mg/dl), quartile 3 (96-102mg/dl), and quartile 4 (102-125mg/dl) versus quartile 1 (<90mg/dl): OR=1.27 (95% CI=1.01-1.60), 1.30 (1.04-1.63), and 1.55 (1.24-1.93), respectively. During the 6-year follow-up, the cumulative incidence of hypertension was greater for people with IFG than normal fasting glucose (NFG) at baseline (23.9% vs 18.4%, p<0.001 for males and 23.8% vs 16.4%, p<0.001 for females). Risk of incident hypertension was significantly increased for females with IFG versus NFG (OR=1.23 95% CI=1.05-1.45).

CONCLUSIONS

IFG may be an independent risk factor for hypertension in normotensive nondiabetic Chinese females.

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.

Changes in Body Weight From Young Adulthood to Middle Age and Its Association With Blood Pressure and Hypertension: A Cross-Sectional Study in Hong Kong Chinese Women

BACKGROUND

Few studies have examined the associations of weight changes from young adulthood to middle age with blood pressure (BP) and hypertension among Hong Kong Chinese women.

METHODS AND RESULTS

Weight at age 18 (W18), current weight (Wcurrent), height, BP, demographics, and lifestyle factors were obtained from 1253 female nurses (35-65 years) by a self-administered questionnaire through mail survey in Hong Kong. The conditional relative weight (CRW; a residual of Wcurrent regressed on W18) was used to express the relative weight change from age 18 to current age. The study results show that from young adulthood to middle age, 76.9%, 15.1%, and 8.0% of women had weight gain, weight loss, and stable weight, respectively. Women in the weight loss group had heavier W18 than those in the weight gain group (P<0.05). Higher weight gain was associated with higher BP (P for trend <0.01). Women who belonged to the heaviest 10% both at age 18 and at present had highest BP than women in other weight categories. By giving W18, a 1-kg increase in weight change predicted 0.63 and 0.42 mm Hg increases in systolic and diastolic BP, respectively (both P<0.001) and 12% greater odds of being hypertension (95% confidence interval, 1.08, 1.17). The CRW was positively associated with BP and hypertension; no interaction was found between CRW and Wcurrent on BP/hypertension.

CONCLUSIONS

A majority of Chinese women tended to become heavier throughout adult life. More weight gain led to the higher BP. Weight change is an independent predictor for later-life BP and hypertension.

Gender differences in the association of hypertension with gamma-glutamyltransferase and alanine aminotransferase levels in Chinese adults in Qingdao, China

The aim of the study was to study the associations of hypertension with gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) levels. Data of 3575 men and 5504 women were analyzed. Multivariate logistic regression analysis was performed to estimate the odds ratio (OR) for hypertension with GGT and ALT. Compared with the lowest quartile, the multivariate adjusted ORs for hypertension were 0.97 (0.79, 1.19) in men and 0.88 (0.74, 1.04) in women for ALT and 2.29 (1.68, 3.14) and 1.52 (1.27, 1.83) for GGT in the highest quartile group. The ORs for hypertension in the low waist circumference category were 2.61 (1.56, 4.36) in men and 1.41 (0.94, 2.12) in women and in the high waist circumference category 4.01 (2.21, 7.29) and 2.26 (1.54, 3.32) for GGT. The elevated GGT, but not ALT, was associated with the presence of the hypertension in men and women. The association is stronger in obese men and women than in their lean counterparts.

Impaired fasting glucose and impaired glucose tolerance do not predict hypertension: a community cohort study

BACKGROUND

Insulin resistance has an important role in the pathogenesis of hypertension. We hypothesized that impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) which represents insulin resistance would predict the development of hypertension.

METHODS

A total of 4,039 subjects without hypertension or diabetes (1,847 men and 2,192 women; age 49.9±8.2 years), from the Ansan-Ansung cohorts within the Korean Genome Epidemiology Study, were enrolled in 2001-2002 and restudied in 2005-2006. The association between the incidence of hypertension and IFG, IGT, or other metabolic factors was studied.

RESULTS

During the 4-year follow-up period, 582 of the 4,039 subjects developed hypertension. At baseline, the prevalence of abdominal obesity, dyslipidemia, and IGT was higher in subjects who became hypertensive compared to those that remained normotensive. The prevalence of IFG was not significantly different between the 2 groups. In a multivariate analysis, abdominal obesity and high serum triglyceride were significant risk factors for the development of hypertension. Neither IFG nor IGT were significantly associated with new-onset hypertension. Although the risk of hypertension was higher with the number of metabolic components present at baseline, IFG and IGT were not significant components compared to other metabolic components, especially when abdominal obesity was taken into account.

CONCLUSIONS

While metabolic syndrome components related to insulin resistance present at baseline are important risk factors of hypertension, we conclude that coexisting metabolic component, mainly abdominal obesity, rather than IFG and IGT have more predictive value for determining the development of hypertension in a Korean population.

The incidental relationship between serum ferritin levels and hypertension

BACKGROUND AND OBJECTIVE

Although several studies have shown an association between ferritin level and hypertension, only a few studies have investigated the longitudinal relationship between them. Thus, we evaluated the incidental risk for hypertension according to baseline ferritin level.

PATIENTS AND METHODS

A total of 7104 healthy Korean men matched by a propensity score, who had participated in a medical health check-up program in 2005, were followed up from 2005 to 2010. They were divided into four groups according to baseline serum ferritin level (first quartile-fourth quartile). The incidence of hypertension was compared among the four groups, and the Cox-proportional hazard model was used to assess whether the development of hypertension was associated with higher baseline serum ferritin level.

RESULTS

A total of 1252 (17.6%) cases had newly developed hypertension during the 26,339.5 person-years of follow-up between 2006 and 2010. The adjusted hazard ratios (HRs) (95% confidence intervals, CIs) for incident hypertension were 1.00 (reference), 1.09 (0.91-1.30), 1.21 (1.01-1.45) and 1.28 (1.07-1.52), respectively (P for trend=0.003) through the quartiles of serum ferritin levels, respectively, after adjusting for multiple confounders. For the log-transformed serum ferritin levels as a continuous variable, adjusted HRs and 95% CIs for HTN were 1.15 (1.02-1.29).

CONCLUSIONS

Elevated serum ferritin level was independently associated with the incidental risk for hypertension in Korean men. This finding suggests the value of elevated ferritin level as an early predictor of hypertension.

Managing blood pressure control in Asian patients: safety and efficacy of losartan

Hypertension is common in Asian populations and is a major cause of cardiovascular diseases. The prevalence of hypertension is increasing in many Asian countries. The overall prevalence of hypertension in India and the People’s Republic of China has been estimated to be 20.6% in men and 22.6% in women. However, the rates of detection, treatment, and control of hypertension remain low in Asia. This reflects a low level of literacy and education, as well as a low level of access to medical care. To overcome these obstacles, strategies targeted at education, promotion, and optimization of medical care, are crucial to achieve target blood pressure control. Angiotensin receptor blockers are one of the first-line treatments for essential hypertension because they confer better cardiovascular outcomes. Losartan has been widely evaluated for the management of hypertension. Although some studies suggested that the blood pressure-lowering effect of losartan is perhaps lower than for other angiotensin receptor blockers, losartan has been demonstrated to be beneficial in terms of renal protection in patients with diabetes, heart failure resulting from either systolic or diastolic dysfunction, and diuretic-induced hyperuricemia. However, most of these data were obtained from Caucasian populations. The efficacy and safety of losartan in Asian populations may be different because of genetic and ethnic variations. Therefore, the efficacy and safety of losartan in Asian patients with hypertension warrant further study.

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.

A single nucleotide polymorphism of interleukin-6 gene is related to plasma adrenomedullin levels

OBJECTIVE

Elevated plasma adrenomedullin (ADM) levels are associated with cardiovascular diseases. Single nucleotide polymorphisms (SNPs) in the gene encoding ADM (ADM) are associated with plasma ADM levels. The presence of a nuclear factor for interleukin-6 (IL-6) expression binding site in the promoter region of the ADM gene suggests a possible relationship between the expression of the ADM and IL-6. Therefore, we investigated whether plasma ADM levels are related to SNPs in the gene encoding IL-6 (IL6).

METHODS

Plasma ADM levels were measured in 476 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2). The subjects were genotyped for three tagging SNPs in the IL6 gene.

RESULTS

The minor allele frequencies of the IL6 SNPs rs17147230, rs1800796 and rs2069837 were 41·8%, 20·0% and 15·4%, respectively. The tagging SNP, rs17147230, was associated with plasma ADM levels after adjusting for age and sex (β=-0·096, P = 0·034). The association was significant in women (β=-0·115, P = 0·021) but not in men. Among all subjects, plasma ADM levels decreased with an increasing number of minor alleles of rs17147230 in multivariate analysis (P = 0·034). Compared to subjects with the AA genotype, subjects with the TT genotype had plasma ADM levels 12·8% lower (95% CI: 0·6-23·5%, P = 0·041). Haplotype analysis demonstrated a significant association of the haplotype ACA with plasma ADM levels in women (P < 0·05).

CONCLUSION

Plasma ADM levels are related to the SNP rs17147230 in IL6 gene. The effect of the polymorphism on inflammation and cardiovascular disease remains to be determined.

Plasma level of adrenomedullin is influenced by a single nucleotide polymorphism in the adiponectin gene

Objective

Adrenomedullin (ADM) and adiponectin are both involved in inflammation and cardiovascular diseases. The plasma levels of these peptides are influenced by single nucleotide polymorphisms (SNPs) in the ADM and ADIPOQ genes respectively. There is some evidence that ADM may regulate adiponectin gene expression, but whether adiponectin can regulate ADM expression is unclear, and was therefore investigated.

Methods

Plasma ADM level was measured in 476 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2). We genotyped them for 2 ADIPOQ SNPs that are known to be associated with plasma adiponectin level.

Results

The minor allele frequencies of ADIPOQ SNPs rs182052 and rs12495941 were 40.6% and 42.2% respectively. Plasma ADM level was significantly associated with rs182052 after adjusting for age and sex (β = 0.104, P = 0.023) but not with rs12495941 (β = 0.071, P = 0.120). In multivariate analysis, plasma ADM level increased with the number of minor alleles of rs182052 (P = 0.013). Compared to subjects with GG genotype, subjects with AA genotype had 17.7% higher plasma ADM level (95% CI: 3.6%–33.7%). Subgroup analysis revealed that the association was significant in diabetic patients (β = 0.344, P = 0.001) but not in non-diabetic subjects.

Conclusion

Plasma ADM level is related to SNP rs182052 in the ADIPOQ gene. Our findings provide new evidence of the interplay between these two important peptides in cardiovascular disease and diabetes. Knowing the genotype may help to refine the interpretation of these biomarkers.

C-reactive protein predicts systolic blood pressure and pulse pressure but not diastolic blood pressure: the Cardiovascular Disease Risk Factors Two-Township Study

OBJECTIVE

Inflammation has been associated with cardiovascular events and mortality, using C-reactive protein (CRP) as a marker. We examined whether the baseline serum concentration of CRP can independently predict the development of hypertension or future systolic or diastolic blood pressure (BP) in a community-based population in Taiwan.

METHODS

A study population sample was recruited in cycle 2 (1990-1993) of the CardioVascular Disease risk FACtors Two-township Study (CVDFACTS) and was followed to 1994-1997. A total of 2,113 nondiabetic adults with normal BP were enrolled for the study of incident hypertension. Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mm Hg, a diastolic blood pressure (DBP) ≥ 90 mm Hg, or the use of antihypertensive drugs. Cox regression and linear regression analyses were used to evaluate the association between baseline serum concentrations of CRP measured with a high-sensitivity assay and the development of hypertension and future SBP/DBP and pulse pressure (PP).

RESULTS

During the follow-up period of a median of 3.27 years, 145 participants developed incident hypertension. The incidence rates of hypertension by tertile of increasing CRP were 9.3, 19.0, and 33.0 per 1,000 person-years (P for trend < 0.01). In the multivariate model adjusted for age, gender, and prehypertension, baseline CRP remained significantly predictive of incident hypertension. The concentration of CRP was associated with SBP and PP, but not with DBP.

CONCLUSION

Inflammation is associated with future SBP in the Taiwanese population.

Impact of hyperinsulinemia on the development of hypertension in normotensive, nondiabetic adults: a 4-year follow-up study

BACKGROUND AND AIMS

This study aimed to investigate the association between baseline fasting insulin levels, changes in fasting insulin levels, and future development of hypertension in normotensive, non-diabetic, healthy adults.

METHODS

We analyzed data from 11,123 adults, aged 20-65years, who had no history of hypertension or diabetes mellitus at a 2004 medical examination in a health promotion program and had attended a repeat examination in 2008. Subjects were divided into four groups according to baseline quartiles of fasting insulin and dichotomized fasting insulin levels at baseline and after 4years: low-low, low-high, high-low, high-high. We also assessed whether the association differed between the younger (20-40years) and older subjects (41-65years).

RESULTS

In four years, 1142 subjects (10.3%) developed hypertension. The odds ratio (OR) for the development for hypertension increased as the quartiles of baseline fasting insulin levels and changes in fasting insulin levels increased from the first to the fourth quartile (OR 1.15, 1.35, and 1.95 vs. 1.07, 1.22, and 1.41, respectively), after adjusting for multiple factors. The OR for hypertension was 2.0-fold higher in the high-high group and 1.34-fold higher in the low-high group than in the low-low group. In comparing the results by age group, we found that these relationships were more prominent in younger subjects.

CONCLUSION

High baseline and continuously increasing fasting insulin levels appeared to be independent determinants for the future development of hypertension during this 4-year follow-up study in normotensive, non-diabetic, healthy adults.

Relationship of plasma interleukin-6 and its genetic variants with hypertension in Hong Kong Chinese

BACKGROUND

Interleukin-6 (IL6) plays a central role in inflammation, insulin resistance, and atherogenesis. We investigated the associations of plasma IL6 and its genetic variants with hypertension in both cross-sectional and prospective study designs.

METHODS

Plasma IL6 was measured in 648 normotensive and 294 hypertensive subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS)-2 in 2000-2004 and three tagging single-nucleotide polymorphisms (SNPs) in the IL6 gene were genotyped. Among subjects normotensive in CRISPS-2 (baseline), 515 subjects were followed-up in CRISPS-3 in 2005-2008 and 100 of them had developed hypertension.

RESULTS

At baseline, plasma IL6 correlated with systolic blood pressure (SBP) (r = 0.128, P < 0.001). Hypertensive subjects had significantly higher plasma IL6 after adjusting for age and sex (geometric mean (95% confidence interval (CI) = 0.60 (0.54-0.65) vs. 0.47 (0.44-0.50) ng/l, P = 0.021). In multiple logistic regression, higher plasma IL6 was associated with hypertension in women (P = 0.009), but not in men. The minor G allele of SNP rs1800796 was associated with lower plasma IL6 (geometric mean (95% CI) = 0.46 (0.41-0.51) ng/l for CG and 0.49 (0.39-0.62) ng/l for GG vs. 0.53 (0.50-0.57) ng/l for CC, P = 0.005). However, this SNP was not associated with hypertension or blood pressure at baseline. Among subjects normotensive in CRISPS-2, plasma IL6 was not associated with the development of hypertension in CRISPS-3.

CONCLUSION

The SNP rs1800796 affected plasma IL6 with a small effect size. Elevated plasma IL6 is associated with prevalent hypertension in women, but not incident hypertension.

Plasma adrenomedullin level is related to a single nucleotide polymorphism in the adrenomedullin gene

OBJECTIVE

Adrenomedullin (ADM) plays an important role in inflammation and is a marker of future cardiovascular events. We studied common single nucleotide polymorphisms (SNPs) in the gene encoding ADM and their relationship with the plasma levels of ADM and other inflammatory markers.

DESIGN AND METHODS

Plasma ADM, interleukin 6 (IL6), fibrinogen, and C-reactive protein (CRP) were measured in 476 subjects from the population-based Hong Kong Cardiovascular Risk Factor Prevalence Study-2. Four tag SNPs in ADM were genotyped.

RESULTS

Plasma ADM level increased with decreasing plasma IL6 level (β=-0.116, P=0.014). Plasma ADM level was not related to plasma levels of CRP and fibrinogen, and other clinical characteristics, except age (P=0.049). The four SNPs, rs3814700, rs11042725, rs34354539, and rs4910118, had minor allele frequencies of 31.1, 28.7, 33.8, and 23.4% respectively. Carriers of the minor allele of rs4910118 had a mean plasma ADM level that was 10.5% (95% confidential interval: 2.5-17.8%) lower than the non-carriers (β=-0.115, P=0.011). Haplotype analysis revealed a similar significant association with plasma ADM (P=0.040). In multivariate analysis, the presence of the minor allele of rs4910118, but not plasma IL6, was independently associated with plasma ADM (P=0.010).

CONCLUSION

Plasma ADM correlates with plasma IL6 level, consistent with its role in inflammation. It is related to an SNP common in Chinese, independent of other covariates. ADM genotype should be included in future studies of cardiovascular risk prediction.

Hyperinsulinemia and homeostasis model assessment of insulin resistance as predictors of hypertension: a 5-year follow-up study of Korean sample

BACKGROUND

The relationships between insulin level and indexes of insulin resistance (IR) to predict incident hypertension have been explored only in cross-sectional or prospective studies with small numbers of patients. We investigated whether plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA(IR)) are associated with the onset of hypertension in a population of apparently healthy and relatively lean Korean adults.

METHODS

We selected 10,894 of 15,638 subjects who were normotensive at baseline during general health status evaluations in 2003 and 2008. The baseline and follow-up examinations included analyses of fasting glucose, insulin level, and lipid profile. Alcohol consumption, smoking status, exercise habits, and education level were also evaluated using a standard questionnaire.

RESULTS

Of the 10,894 subjects, hypertension developed in 881 (8.1%) during the ensuing 5 years. Incident hypertension was more common among older subjects than it was in younger subjects and was associated with a high baseline body mass index (BMI). In multivariable logistic models, elevated serum insulin, and HOMA(IR) were associated with an increased risk of incident hypertension in both sexes. In a multivariable analysis using quartiles of insulin and HOMA(IR), the odds ratio (OR) for incident hypertension was the highest in the highest quartile of insulin and HOMA(IR). The highest quartile of insulin and HOMA(IR) was associated with a 1.5-1.7 times increased risk of incident hypertension.

CONCLUSIONS

This 5-year follow-up study provides evidence that both a high circulating insulin level and HOMA(IR) are significant risk factors for the development of hypertension in a relatively lean and healthy population.

The role of β-blockers in the management of hypertension: an Asian perspective

Following publication of the National Institute of Clinical Excellence (NICE) Guidelines in 2006, the use of β-blockers as first-line therapy in hypertension has been somewhat controversial. However, a recent reappraisal of the European Society of Hypertension guidelines highlights that these agents exhibit similar BP lowering efficacy to other classes of agents, prompting a re-examination of the utility of these agents in various patient populations. The authors felt that it is important to address this controversy and provide an Asian perspective on the place of β-blockers in current clinical practice and the benefits of β-blockade in selected patient populations. In addition to their use as a potential first-line therapy in uncomplicated hypertension, β-blockers have a particular role in patients with hypertension and comorbidities such as heart failure or coronary artery disease, including those who had a myocardial infarction. One advantage which β-blockers offer is the additional protective effects in patients with prior cardiovascular events. Some of the disadvantages attributed to β-blockers appear more related to the older drugs in this class and further appraisal of the efficacy and safety profile of newer β-blockers will lend support to the current guideline recommendations in Asian countries and encourage increased appropriate use of β-blockade in current clinical practice within Asia.

Gamma-glutamyl transferase level predicts the development of hypertension in Hong Kong Chinese

BACKGROUND

Plasma activities of alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase, and γ-glutamyl transferase (GGT) are often increased in cardiometabolic diseases. We investigated if hypertension is associated with increased activities of these plasma markers.

METHODS

We included 235 hypertensive and 708 normotensive subjects (mean age 47.3±9.6 and 58.0±10.2 years respectively) from the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS-2) in 2000-2004 who had drank <1/week. In the follow-up study in 2005-2008 (CRISPS-3), 126 out of the 708 subjects had developed hypertension.

RESULTS

Raised plasma ALT (OR=1.22 per SD of log-transformed level, P=0.045) and GGT (OR=1.38 per SD of log-transformed level, P=0.001) levels were associated with hypertension at baseline in CRISPS-2 after adjusting for covariates. Among subjects not on anti-hypertensive medications, plasma ALP, ALT and GGT were related to blood pressure (P<0.01). In subjects normotensive at CRISPS-2, plasma GGT, but not ALP, ALT and AST, was an independent predictor of new-onset hypertension at CRISPS-3 (OR=1.38 per SD of log-transformed level, P=0.020 and OR=2.68 for 3rd tertile vs. 1st tertile, P=0.004) after adjusting for covariates.

CONCLUSIONS

Among the 4 plasma markers, increased GGT activity is the strongest predictor for existing and new-onset hypertension in Hong Kong Chinese.

Association of a genetic variant in the apolipoprotein A5 gene with the metabolic syndrome in Chinese

OBJECTIVE

Single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 gene (APOA5) are associated with hypertriglyceridaemia in our population. We studied the associations of SNPs in APOA5 with the metabolic syndrome (MetS) in the Hong Kong and Guangzhou Chinese.

METHODS

We genotyped five tagging SNPs in 1330 unrelated subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study cohort with follow-up after a median interval of 6·4 years; 1952 subjects from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort were used to replicate the findings. The MetS was defined according to the consensus criteria proposed jointly by several organizations in 2009.

RESULTS

The SNP rs662799 (-1131T>C) was associated with the MetS (odds ratio = 1·47, P = 0·00082) and the number of its components present (regression coefficient = 0·204, P = 4·6 × 10(-5) ) after adjusting for age, sex, smoking, drinking and education in Hong Kong subjects at baseline. Similar association of this SNP was found in Hong Kong subjects at follow-up (P = 0·010 and 0·00021, respectively) and in Guangzhou subjects (P = 0·0041 and 0·017, respectively). The association of rs662799 with the number of the MetS components was significant regardless of age, sex, obesity and alcohol drinking, but almost disappeared after further adjusting for plasma triglycerides.

CONCLUSION

Our results showed that the -1131T>C polymorphism in APOA5 was associated with the MetS because of its strong effect on plasma triglycerides. This may partly explain the higher cardiovascular risk in people with this polymorphism.

A genetic variant in the gene encoding adrenomedullin predicts the development of dysglycemia over 6.4 years in Chinese

BACKGROUND

Adrenomedullin, a vasodilatory peptide, facilitates the differentiation of pre-adipocytes, and affects lipolysis and glucose uptake. We investigated the association of common single nucleotide polymorphisms (SNPs) in the gene encoding adrenomedullin (ADM) with dysglycemia in the Hong Kong Chinese population.

METHODS

Four SNPs were genotyped in 1391 subjects without dysglycemia at baseline from the Hong Kong Cardiovascular Risk Factor Prevalence Study-2, which had a median follow-up time of 6.4 years. Dysglycemia included impaired fasting glucose, impaired glucose tolerance, and diabetes according to the WHO 1998 criteria. At follow-up, 382 subjects had developed dysglycemia.

RESULTS

In stepwise logistic regression, the SNP rs11042725 was a significant independent predictor of the development of dysglycemia (OR=1.31, P=0.012), together with baseline age (P<0.001), plasma triglycerides (P<0.001), body mass index (P=0.004), 2-h glucose after oral glucose tolerance test (P<0.001), homeostasis model assessment of insulin resistance index (P=0.045), and follow-up duration (P=0.009). The association was more significant in women (P=0.002) and in subjects without regular exercise (P=0.001).

CONCLUSIONS

Our study suggests a potential role of genetic variants in the ADM gene in the development of dysglycemia in our local Chinese population.

The hypertension-diabetes continuum

Hypertension and type 2 diabetes are both common chronic conditions that affect a major proportion of the general population. They tend to occur in the same individual, suggesting common predisposing factors, which can be genetic or environmental. Although the genes causing hypertension or diabetes await elucidation, the environmental causes of these diseases are well known. Obesity and physical activity are the 2 leading factors that predispose to both diseases. Individuals with abdominal obesity are likely to develop lipid abnormalities and elevation of blood pressure and glucose. In time, hypertension and diabetes ensue. Because of the shared etiology, there is substantial overlap between hypertension and diabetes. In the Hong Kong Cardiovascular Risk Factor Prevalence Study, 40% of the subjects in the community had either raised blood pressure or raised blood glucose. Only 42% of people with diabetes had normal blood pressure and only 56% of people with hypertension had normal glucose tolerance. The presence of hypertension or diabetes should alert the clinician to the possibility of the other condition. Obesity, lipid abnormalities, raised blood pressure, and glucose are all components of the metabolic syndrome. The syndrome therefore implies a pathologic process, which is potentially reversible in the early stages. Previous efforts targeting smoking, hypertension, and hypercholesterolemia have started to bear fruit. However, obesity is on the increase in developed and developing countries. It is now time to focus on obesity and the metabolic syndrome, which require more a public health than a pharmacologic approach.

A community-based study of hypertension and cardio-metabolic syndrome in semi-urban and rural communities in Nigeria

Background

The prevalence of cardio-metabolic syndrome (CMS) is increasing worldwide. In people of African descent, there is higher prevalence of hypertension and complications than other races. Bearing in mind these facts, we looked at the CMS in the general population and the population with hypertension. Using the new International Diabetes Federation (IDF) definitions of CMS, we studied its prevalence in semi-urban and rural communities in South-east Nigeria in relation to hypertension.

Method

This is a cross sectional population based study involving 1458 adults aged from 25 to 64 years. Diagnosis of CMS was based on the new IDF criteria using the anthropometric measurements for Europids as there is none yet for blacks. Hypertension was defined according to the WHO/ISH criteria.

Results

The overall prevalence of CMS was 18.0% in the semi-urban community as against 10.0% in the rural community increasing to 34.7% and 24.7% respectively in the population with hypertension. The prevalence of co-morbidities - hyperglycaemia, abdominal obesity, and hypertriglceridaemia were 13.9%, 41.1% and 23.9% while in the hypertensive populations they were 21.2%, 55.0% and 31.3% in the general population in both communities combined. Except for low HDL cholesterol, every other co-morbidity was higher in hypertensive population than the general population.

Conclusion

The high prevalence of CMS in the semi-urban population especially for the population with hypertension underscores the double burden of disease in developing countries. The lesson is while infections and infestations are being tackled in these countries the non-communicable diseases should not be neglected.

High density lipoprotein-cholesterol levels increase with age in American women but not in Hong Kong Chinese women

OBJECTIVES

High-density lipoprotein (HDL) cholesterol is a powerful cardiovascular risk factor. Important gender and ethnic differences in plasma HDL levels exist and warrant investigation.

DESIGN

Cross-sectional survey in two different general populations. Patients 7700 participants of the National Health and Nutrition Examination Survey (NHANES) 1999-2002 and 1944 participants of the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS2) 2000-2004.

MEASUREMENTS

Plasma HDL levels.

RESULTS

Plasma HDL levels were higher in women than in men in both populations. In the United States women, it increased with age, whereas in Chinese women, it declined with age and converged with male HDL levels. In the United States, 37.1 +/- 1.2% men and 38.9 +/- 1.1% women had low HDL levels. In Hong Kong, 34.3 +/- 1.6% men and 34.5 +/- 1.5% women had low HDL levels. In Americans, the independent predictors of low HDL levels were lower age, being non-Mexican Hispanic, waist circumference, triglycerides and not drinking alcohol in men, and lower age, being Hispanic, waist circumference, triglycerides, current smoking and not drinking alcohol in women. In Hong Kong Chinese, the independent predictors of low HDL levels were body mass index, triglycerides, current smoking and not drinking alcohol in men, and lower age, waist circumference, triglycerides, diabetes and former smoking in women.

CONCLUSIONS

The decline in plasma HDL with age in Chinese women is opposite to that seen in American women. The increased cardiovascular risk in elderly Chinese women requires further study.

Association between raised blood pressure and dysglycemia in Hong Kong Chinese

OBJECTIVE

To investigate the association between raised blood pressure and dysglycemia.

RESEARCH DESIGN AND METHODS

We studied the association between raised blood pressure and dysglycemia in 1,862 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study cohort. We determined the factors predicting the development of diabetes and hypertension in 1,496 subjects who did not have either condition at baseline.

RESULTS

Diabetes and hypertension were both related to age, obesity indexes, blood pressure, glucose, HDL cholesterol, and triglycerides. Of subjects with diabetes, 58% had raised blood pressure. Of subjects with hypertension, 56% had dysglycemia. BMI and blood glucose 2 h after a 75-g oral glucose load were independent predictors of new-onset diabetes. Age, systolic blood pressure, and 2-h glucose were independent predictors of new-onset hypertension. BMI, systolic blood pressure, and 2-h glucose were independent predictors of the development of diabetes and hypertension together.

CONCLUSIONS

Diabetes and hypertension share common etiological factors. Patients with diabetes or hypertension should be screened and managed for the precursor of the other condition.

Association between plasma alkaline phosphatase and C-reactive protein in Hong Kong Chinese

BACKGROUND

Alkaline phosphatase (ALP) is a biomarker for hepatobiliary and skeletal diseases. It is also raised in sepsis. In atherosclerotic plaques, ALP is expressed. Similar to C-reactive protein (CRP), it may be another marker of systemic inflammation. Therefore, we investigated their association in a Hong Kong Chinese population.

METHODS

Plasma ALP and CRP were measured in 205 subjects (110 men, 95 women; age 55.2+/-11.6 years) in the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 cohort.

RESULTS

The blood levels of ALP and CRP were significantly correlated (r=0.30, p<0.001), which was due to a significant correlation in women (r=0.43, p<0.001). In a multivariate model, CRP level was related to ALP (beta=0.18, p=0.008). After adjusting for confounding factors and other liver enzymes, the relationship between ALP and CRP remained significant in women (beta=0.28, p=0.019), but in men, ALP was not an independent determinant of CRP levels.

CONCLUSIONS

ALP may be another marker of systemic inflammation, especially in women. Whether it provides clinical information additional to CRP requires further study.

Components of the metabolic syndrome predictive of its development: a 6-year longitudinal study in Hong Kong Chinese

OBJECTIVE

To investigate which of the components of the metabolic syndrome best predict its development.

DESIGN

Long-term cohort of randomly selected adults.

PATIENTS

One thousand five hundred and forty-eight subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study who did not have the metabolic syndrome by the US National Cholesterol Education Program (NCEP) or International Diabetes Federation (IDF) criteria at baseline.

MEASUREMENTS

Waist circumference, blood pressure, glucose, triglycerides and high-density lipoprotein-cholesterol (HDL).

RESULTS

After a median interval of 6.4 years, there were 219 and 143 new cases (21.9 and 14.3 per 1000 person-years) of the metabolic syndrome by the NCEP and IDF criteria, respectively. The odds ratio for the NCEP metabolic syndrome was highest for low HDL, 4.08 [95% confidence interval (CI): 2.90-5.73] and that for the IDF metabolic syndrome was highest for central obesity, 5.94 [95% CI: 3.98-8.87]. Low HDL, found in 27.8% men and 34.3% women, had the highest sensitivity for the NCEP metabolic syndrome (48% in men and 57% in women) and the IDF metabolic syndrome (41% in men and 54% in women). Central obesity had the highest positive predictive values except that triglycerides had the highest positive predictive value for the NCEP metabolic syndrome in women. The areas under the receiver operator characteristic curve for waist circumference, triglycerides and HDL were similar. A model that included waist circumference and HDL predicted the metabolic syndrome as well as a model that included all five metabolic syndrome components.

CONCLUSION

Obese Chinese adults should be periodically screened for the metabolic syndrome and have waist and HDL measurement.

Association of a polymorphism in the lipin 1 gene with systolic blood pressure in men

BACKGROUND

Lipin 1 plays a role in abdominal obesity, insulin resistance, and hypertriglyceridemia. The gene is located at 2p25.1, a susceptibility locus for hypertension. We studied the association of tagging single-nucleotide polymorphisms (SNPs) in the lipin 1 (LPIN1) gene with hypertension and blood pressure.

METHODS

Twelve tagging SNPs from the HapMap database were genotyped using Sequenom MassArray in 268 hypertensive subjects and 407 normotensive controls, of whom 268 matched the cases in age and sex.

RESULTS

None of the tagging SNPs were found to be associated with hypertension after correcting for multiple testing, although carriers of the minor allele of rs10520097 had nominally lower odds for hypertension (P = 0.014). After excluding subjects who were on antihypertensive medications, the minor allele of rs10495584 was nominally associated with lower mean systolic and diastolic blood pressures in men (121.1 +/- 14.2 and 76.3 +/- 10.2 mm Hg vs. 127.4 +/- 15.2 and 80.1 +/- 10.5 mm Hg, P = 0.002 and 0.007, respectively), but not in women (P > 0.05). The association of rs10495584 with systolic blood pressure in men remained significant after correcting for multiple testing and adjustment for age, waist circumference, insulin resistance, triglyceride, and high-density lipoprotein (HDL) cholesterol (beta = -0.158, P = 0.005). An analysis of statistically similar SNPs (ssSNPs) in the regions surrounding rs10495584 suggested that its effect may be caused by its high linkage disequilibrium (LD) with the SNP, rs11524, in which the major allele forms an exonic splicing silencer sequence.

CONCLUSION

Our study provides further evidence that lipin 1 may play a role in blood pressure regulation, especially in men.