Background

Observational studies have reported an inverse association between dietary protein intake and blood pressure (BP). We compared the effect of soy protein, milk protein, and carbohydrate supplementation on BP among healthy adults.

Methods and Results

We conducted a randomized double-blind crossover trial with 3-intervention phases among 352 adults with prehypertension or stage-1 hypertension in New Orleans, Louisiana and Jackson, Mississippi from September 2003 to April 2008. The trial participants were assigned to take 40 grams/day of soy protein, milk protein, or carbohydrate supplementation each for 8 weeks in a random order. A 3-week washout period was implemented between the interventions. Three BPs were measured at 2 baseline and 2 termination visits during each of 3 intervention phases using a random-zero sphygmomanometer. Compared to carbohydrate controls, soy protein and milk protein supplementations were significantly associated with −2.0 mmHg (95% confidence interval −3.2 to −0.7, p=0.002) and −2.3 mmHg (−3.7 to −1.0, p=0.0007) net change in systolic BP, respectively. Diastolic BP was also reduced but this change did not reach statistical significance. There was no significant difference in the BP reductions achieved between soy or milk protein supplementation.

Conclusions

The results from this randomized controlled trial indicate that both soy and milk protein intake reduce systolic BP compared to a high glycemic index refined carbohydrate among patients with prehypertension and stage-1 hypertension. Furthermore, these findings suggest that partially replacing carbohydrate with soy or milk protein might be an important component of nutrition intervention strategies for the prevention and treatment of hypertension.

Background

Few data are available evaluating the associations of formal public health education with long-term career choice and professional outcomes among medical school graduates. The objective of this study was to determine if formal public health education via completion of a masters of public health (MPH) degree among US medical school graduates was associated with early and long-term career choice, professional satisfaction, or research productivity.

Methods

We conducted a retrospective cohort study in 1108 physicians (17.1% completed a MPH degree) who had 10–20 years of follow-up post medical school graduation. Multivariable logistic regression analyses were conducted.

Results

Compared to their counterparts with no MPH, medical school graduates with a MPH were more likely to have completed a generalist primary care residency only [relative risk (RR) 1.79, 95% confidence interval (CI) 1.35–2.29], obtain employment in an academic institution (RR 1.81; 95% CI 1.33–2.37) or government agency (RR 3.26; 95% CI 1.89–5.38), and practice public health (RR 39.84; 95% CI 12.13–107.38) or primary care (RR 1.59; 95% CI 1.18–2.05). Furthermore, medical school graduates with a MPH were more likely to conduct public health research (RR 8.79; 95% CI: 5.20–13.82), receive NIH or other federal funding (RR 3.11, 95% CI 1.74–5.33), have four or more peer-reviewed publications (RR 2.07; 95% CI 1.56–2.60), and have five or more scientific presentations (RR 2.31, 95% CI 1.70–2.98).

Conclusion

Formal public health education via a MPH was associated with career choice and professional outcomes among physicians.

Objectives

The purpose of this study was to examine the association between genetic variants in the renin-angiotensin system (RAS) and blood pressure (BP) responses to cold pressor test (CPT).

Methods

The CPT was conducted among 1,998 Han Chinese participants. BP measurements were obtained before and after the CPT using a standard sphygmomanometer according to a standard protocol. The association between SNP genotypes and BP responses to the CPT was assessed using a mixed linear model.

Results

Of 68 SNPs genotyped in 6 RAS genes, two were strongly associated with diastolic BP (DBP) responses to CPT (P ≤ 0.001; false discovery rate q-value < 0.05): rs2006765 and rs943580 in the angiotensinogen (AGT) gene. Compared to C allele carriers of rs2006765, the TT homozygotes had a significantly decreased DBP response to the CPT. For participants with the TT genotype, percent DBP responses were 5.68% (4.25%, 7.10%), compared to corresponding responses of 9.17% (8.66%, 9.68%) among participants with the CC+CT genotype. In addition, SNP rs4681443 of the angiotensin type 1 receptor (AGTR1) gene was significantly associated with percent SBP responses to CPT (P≤0.001; q-value <0.05).

Conclusion

Briefly, our study identified variants in the AGT and AGTR1 genes that may influence BP responses to CPT in Han Chinese population. These results show that genetic variants in the RAS play an important role in BP responses to CPT, and therefore in predicting future hypertension.

Background

We examined the association of biomarkers of inflammation and endothelial dysfunction with diabetes and metabolic syndrome (MetS) in persons from Inner Mongolia.

Methods

A cross-sectional study was conducted among 2,536 people aged 20 years and older from Inner Mongolia, China. Overnight fasting blood samples were obtained to measure plasma concentrations of high sensitivity C-reactive protein (hsCRP), soluble inter-cellular adhesion molecule-1 (sICAM-1), sE-selectin, angiotensin II, high density lipoprotein cholesterol, triglycerides, and blood glucose. Waist circumference and blood pressure were measured by trained staff. MetS was defined according to the modified ATP III definition for Asians. Elevated level of the biomarker was defined as values in the upper tertile of the distribution. Participants were categorized into one of four groups based on the presence or absence of metabolic and glycemic abnormalities: 1) free of prediabetes, diabetes and MetS (reference group), 2) prediabetes or diabetes only, 3) MetS without prediabetes or diabetes, and 4) MetS plus prediabetes or diabetes. The multivariable models are adjusted for age, gender, smoking, drinking, family history of hypertension, and body mass index.

Results

Among study participants, 18.5% had prediabetes, 3.6% had diabetes, and 27.4% of the entire study population had 3 or more components of the MetS. Elevated hsCRP was associated with an increased odds of prediabetes or diabetes only, MetS without prediabetes or diabetes, and MetS plus prediabetes or diabetes with multivariable adjusted odds ratios (95% confidence intervals) of 2.3 (1.7-3.1), 3.0 (2.4-3.8), and 5.8 (4.5-7.5), respectively. Elevated sICAM-1 was associated with increased odds (95% CI) of prediabetes or diabetes only (2.1, 1.6-2.9) and MetS plus prediabetes or diabetes (4.2, 3.2-5.3) but was not associated with MetS alone. Elevated sE-selectin was associated with a modestly increased risk of MetS (OR 1.7, 95% CI 1.4-2.2). Elevated levels of Angiotensin II were not associated with the MetS plus prediabetes or diabetes in this study.

Conclusions

Diabetes and the MetS are common in the Inner Mongolia population. The biomarkers of inflammation and endothelial dysfunction are associated with increased risk for diabetes and MetS in this population. These results are consistent with results from other populations.

Background

Premature death from suicide is a leading cause of death worldwide. However, the pattern and risk factors for suicide and other external cause injuries are not well understood. This study investigates mortality from suicide and other injuries and associated risk factors in China.

Methods

A prospective cohort study of 169,871 Chinese adults aged 40 years and older was conducted. Mortality due to suicide or other external cause injuries was recorded.

Results

Mortality from all external causes was 58.7/100,000 (72.3 in men and 44.4 in women): 14.1/100,000 (14.2 in men and 14.2 in women) for suicide and 44.6/100,000 (58.1 in men and 30.2 in women) for other external cause injuries. Transport accidents (17.2/100,000 overall, 23.4 in men and 10.8 in women), accidental poisoning (7.5/100,000 overall, 10.2 in men and 4.8 in women), and accidental falls (5.7/100,000 overall, 6.5 in men and 5.0 in women) were the three leading causes of death from other external cause injuries in China. In the multivariable analysis, male sex (relative risk [RR] 1.56, 95% confidence interval [CI] 1.03-2.38), age 70 years and older (2.27, 1.29-3.98), living in north China (1.68, 1.20-2.36) and rural residence (2.82, 1.76-4.51) were associated with increased mortality from suicide. Male sex (RR 2.50, 95% CI 1.95-3.20), age 60-69 years (1.93, 1.45-2.58) and 70 years and older (3.58, 2.58-4.97), rural residence (2.29, 1.77-2.96), and having no education (1.56, 1.00-2.43) were associated with increased mortality from other external cause injuries, while overweight (0.60, 0.43-0.83) was associated with decreased risk of mortality from other external cause injuries.

Conclusions

External cause mortality has become a major public health problem in China. Developing an integrated national program for the prevention of mortality due to external cause injuries in China is warranted.

BACKGROUND

Genetic factors may influence blood pressure (BP) responses to dietary potassium intake. We examined the association of genetic variants in the apelin-APJ system and angiotensin-converting enzyme 2 (ACE2) with BP responses to potassium supplementation.

METHODS

We conducted a 7-day potassium supplementation (60 mmol/day) intervention among 1,906 Chinese adults who participated in the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. Tag single nucleotide polymorphisms (SNPs) based on HapMap data and potential functional SNPs were selected in the APLN, APLNR, and ACE2 genes. Because the ACE2 and APLN genes are located on the X chromosome, men and women were analyzed separately.

RESULTS

In women, SNP rs2235306 in the APLN gene was significantly associated with diastolic BP (DBP) response to potassium supplementation (P=0.0009). The DBP responses [95% confidence interval (CI)] among those with genotypes T/T, T/C, and C/C were −2.22 (−2.74, −1.70), −1.69 (−2.20, −1.19), and −0.81 (−1.54, −0.09) mmHg, respectively. In men, SNP rs4646174 of the ACE2 gene was significantly associated with systolic BP (SBP), DBP, and mean arterial pressure (MAP) responses to potassium supplementation (P=0.0001, P=0.001, and P=3.0×10−6, respectively). The SBP, DBP and MAP responses (95% CI) were −0.79 (−2.27, 0.69) versus −3.53 (−3.94, −3.12), 1.07 (−0.34, 2.49) versus −1.06 (−1.43, −0.69), and 0.44 (−0.60, 1.48) versus −1.89 (−2.22, −1.55) mmHg among men with minor G allele compared to those with major C allele of rs4646174, respectively.

CONCLUSIONS

Our study indicates that genetic variation of APLN and ACE2 may influence BP response to potassium intake.

Background

The relative effects of individual and combined risk factor trends on future cardiovascular disease in China have not been quantified in detail.

Methods and Results

Future risk factor trends in China were projected based on prior trends. Cardiovascular disease (coronary heart disease and stroke) in adults ages 35 to 84 years was projected from 2010 to 2030 using the Coronary Heart Disease Policy Model–China, a Markov computer simulation model. With risk factor levels held constant, projected annual cardiovascular events increased by >50% between 2010 and 2030 based on population aging and growth alone. Projected trends in blood pressure, total cholesterol, diabetes (increases), and active smoking (decline) would increase annual cardiovascular disease events by an additional 23%, an increase of approximately 21.3 million cardiovascular events and 7.7 million cardiovascular deaths over 2010 to 2030. Aggressively reducing active smoking in Chinese men to 20% prevalence in 2020 and 10% prevalence in 2030 or reducing mean systolic blood pressure by 3.8 mm Hg in men and women would counteract adverse trends in other risk factors by preventing cardiovascular events and 2.9 to 5.7 million total deaths over 2 decades.

Conclusions

Aging and population growth will increase cardiovascular disease by more than a half over the coming 20 years, and projected unfavorable trends in blood pressure, total cholesterol, diabetes, and body mass index may accelerate the epidemic. National policy aimed at controlling blood pressure, smoking, and other risk factors would counteract the expected future cardiovascular disease epidemic in China.

BACKGROUND

Genetic determinants of blood pressure (BP) responses to the cold pressor test (CPT), a phenotype associated with risk of hypertension and cardiovascular disease has not been well studied.

METHODS

We examined the heritability of BP response to CPT in 1,994 subjects from 627 families in rural north China. BP was measured prior to and at 0, 1, 2, and 4 minutes after the participants immersed their hand in ice water for 1 minute. Heritabilities of baseline BP and responses at 0 minutes, maximum response, and area-under-the-curve during CPT were computed using a variance components method. Additionally, bivariate heritabilities were calculated to test the existence of shared genetic determinants between baseline BP and responses to CPT.

RESULTS

Heritabilities of baseline BP and responses to CPT were estimated from 14% to 35%, which all significantly differed from 0 (p≤0.002). Genetic correlations (standard error) due to the same genes between baseline BP and responses to CPT ranged from −0.07 (0.14) to 0.21 (0.15), which were not significantly different from 0. Genetic correlations between reactivity and recovery were 0.67 (0.10) and 0.59 (0.10) for systolic and diastolic BP, respectively, which were significantly different from 0.

CONCLUSIONS

We concluded: 1) baseline BP and BP responses to CPT had strong genetic determinants; 2) baseline BP and BP response to CPT did not share the same genetic components; and 3) BP reactivity and recovery shared the same genetic components. These findings may lead to a better understanding of the genetic mechanism of BP responses to CPT.

Objective

To examine factors related to blood pressure (BP) responses to dietary sodium and potassium interventions.

Methods

We conducted a dietary feeding study that included a 7-day low-salt intervention (51.3 mmol/day), a 7-day high-salt intervention (307.8 mmol/day), and a 7-day high-salt plus potassium supplementation (60 mmol/day) intervention among 1,906 study participants in rural China. BP was measured 9 times during the 3-day baseline observation and during the last 3 days of each intervention phase using a random-zero sphygmomanometer.

Results

BP responses to low-sodium intervention were significantly greater in women compared to men: –8.1 (95% confidence interval (−8.6 to −7.6) versus −7.0 (−7.5 to −6.6) mmHg for systolic and −4.5 (−4.9 to −4.1) versus −3.4 (−3.8 to −3.0) mmHg for diastolic. Likewise, BP responses to high-sodium interventions were significantly greater in women compared to men: 6.4 (5.9 to 6.8) versus 5.2 (4.8 to 5.7) mmHg for systolic and 3.1 (2.7 to 3.5) versus 1.7 (1.4 to 2.1) mmHg for diastolic (all p<0.001). In addition, systolic BP responses to the sodium interventions increased with age and both systolic and diastolic BP responses to the sodium interventions increased with baseline BP levels. BP responses to potassium supplementation also increased with baseline BP levels.

Conclusions

These results suggest that female gender, older age, and hypertension increase sensitivity to dietary sodium intervention. Furthermore, low dietary sodium intake may be more effective in reducing BP among these subgroups.

Background and Purpose

We studied the relationship between cigarette smoking and stroke incidence and mortality in the Chinese adult population.

Methods

We conducted a prospective cohort study in a nationally representative sample of 169,871 Chinese men and women aged 40 years and older. Data on cigarette smoking and other covariables were collected at a baseline examination in 1991 using a standard protocol. Follow-up evaluation was conducted in 1999-2000, with a response rate of 93.4%.

Results

During an average of 8.3 years follow-up, a total of 6,780 stroke events (3,979 fatal strokes) were observed. The multivariate-adjusted relative risks (95% confidence interval) of stroke incidence and mortality associated with current cigarette smoking were 1.28 (1.19-1.37) and 1.13 (1.03-1.25) in men and 1.25 (1.13-1.37) and 1.19 (1.04-1.36) in women, respectively. The corresponding population attributable risks were 14.2% and 7.1% in men and 3.1% and 2.4% in women. Compared to never-smokers, the multivariate-adjusted relative risks of stroke incidence (95% confidence interval) were 1.21 (1.12-1.31), 1.21 (1.11-1.32), and 1.36 (1.25-1.47) for those who smoked 1-9, 10-19, and ≥20 cigarettes per day; and 1.18 (1.09-1.28), 1.25 (1.15-1.35), and 1.34 (1.24-1.44) for those who smoked 1-11, 12-26, and >26 pack-years, respectively (both p <0.0001 for linear trends).

Conclusions

Our study identified a positive and dose-response relationship between cigarette smoking and risk of stroke. Smoking prevention and cessation programs should be an important strategy for reducing the burden of stroke in Chinese adults.

Summary

Background

We aimed to examine the association between the metabolic syndrome and salt-sensitivity of blood pressure (BP).

Methods

1,906 Chinese aged ≥16 years without diabetes were fed a low-sodium diet (51.3 mmol/day) for 7 days followed by a high-sodium diet (307.8 mmol/day) for an additional 7 days. BP were measured at baseline and at the end of each intervention period using a random-zero sphygmomanometer. Metabolic syndrome was defined as the presence of ≥3 risk factors: abdominal obesity, high triglyceride, low high-density-lipoprotein-cholesterol, elevated BP, and elevated glucose.

Findings

Multivariable-adjusted mean changes (95% confidence intervals) in BP (mmHg) were significantly greater (all p<0.0001) among participants with compared to those without the metabolic syndrome: −7.34 (−8.21, −6.46) versus −5.17 (−5.51, −4.83) for systolic BP and −4.56 (−5.28, −3.85) versus −2.47 (−2.74, −2.19) for diastolic BP during the low-sodium intervention; and 6.51 (5.76, 7.26) versus 4.55 (4.26, 4.84) for systolic BP and 3.25 (2.56, 3.94) versus 1.69 (1.42, 1.96) for diastolic BP during the high-sodium intervention. In addition, compared to those with zero, participants with 4 or 5 risk factors for the metabolic syndrome had a 3.54-fold increased odds (2.05, 6.11) of high salt-sensitivity during the low-sodium intervention and a 3.13-fold increased odds (1.80, 5.43) of high salt-sensitivity during the high-sodium intervention.

Interpretation

These results suggest that the metabolic syndrome significantly enhances BP response to sodium intake. Reduction in sodium intake may be an especially important component in reducing BP among patients with multiple risk factors for the metabolic syndrome.

Background

China will experience an overall growth and aging of its adult population in coming decades. We used a computer model to forecast the future impact of these demographic changes on coronary heart disease (CHD) in China.

Methods

The CHD Policy Model is a validated state-transition, computer simulation of CHD on a national scale. China-specific CHD risk factor, incidence, case-fatality, and prevalence data were incorporated, and a CHD prediction model was generated from a Chinese cohort study and calibrated to age-specific Chinese mortality rates. Disability-adjusted life years (DALYs) due to CHD were calculated using standard methods. The projected population of China aged 35–84 years was entered, and CHD events, deaths, and DALYs were simulated over 2000–2029. CHD risk factors other than age and case-fatality were held at year 2000 levels. Sensitivity analyses tested uncertainty regarding CHD mortality coding, the proportion of total deaths attributable to CHD, and case-fatality.

Results

We predicted 7.8 million excess CHD events (a 69% increase) and 3.4 million excess CHD deaths (a 64% increase) in the decade 2020–2029 compared with 2000–2009. For 2030, we predicted 71% of almost one million annual CHD deaths will occur in persons ≥65 years old, while 67% of the growing annual burden of CHD death and disability will weigh on adults <65 years old. Substituting alternate CHD mortality assumptions led to 17–20% more predicted CHD deaths over 2000–2029, though the pattern of increases in CHD events and deaths over time remained.

Conclusion

We forecast that absolute numbers of CHD events and deaths will increase dramatically in China over 2010–2029, due to a growing and aging population alone. Recent data suggest CHD risk factor levels are increasing, so our projections may underestimate the extent of the potential CHD epidemic in China.

Background

Blood pressure (BP) responses to the cold pressor test (CPT) and to dietary sodium intake might be related to the risk of hypertension. We examined the association between BP responses to the CPT and to dietary sodium and potassium interventions.

Methods

The CPT and dietary intervention were conducted among 1,906 study participants in rural China. The dietary intervention included three 7-day periods of low-sodium-feeding (51.3 mmol/day), high-sodium-feeding (307.8 mmol/day), and high-sodium-feeding plus potassium-supplementation (60 mmol/day). A total of 9 BP measurements were obtained during the 3-day baseline observation and the last 3 days of each intervention using a random-zero sphygmomanometer.

Results

BP response to the CPT was significantly associated with BP changes during the sodium and potassium interventions (all p<0.0001). Compared to the lowest quartile of BP response to the CPT, systolic BP changes (95% confident interval) for the top 3 quartiles, respectively, were −2.02 (−2.87, −1.16), −3.17 (−4.05, −2.28), and −5.98 (−6.89, −5.08) mm Hg during the low-sodium intervention. Corresponding systolic BP changes during the high-sodium intervention were 0.40 (−0.36, 1.16), 0.44 (−0.35, 1.22), and 2.30 (1.50, 3.10) mm Hg, and during the potassium-supplementation were −0.26 (−0.99, 0.46), −0.95 (−1.70, −0.20), and −1.59 (−2.36, −0.83) mm Hg, respectively.

Conclusions

These results indicated that BP response to the CPT was associated with salt-sensitivity and potassium-sensitivity. Furthermore, a low-sodium or high-potassium diet might be more effective to lower BP among individuals with high responses to the CPT.

The heritability of blood pressure responses to dietary intervention has not been well studied. We examined the heritability of blood pressure responses to dietary sodium and potassium intake in a family feeding-study among 1,906 study participants living in rural north China. The dietary intervention included a 7-day low sodium-feeding (51.3 mmol/day), a 7-day high sodium-feeding (307.8 mmol/day), and a 7-day high-sodium plus potassium-supplementation (60 mmol/day). Blood pressure was measured 9 times during the 3-day baseline period preceding the intervention and also during the last 3 days of each intervention phase using a random-zero sphygmomanometer. Heritability was computed using maximum likelihood methods under a variance components model as implemented in the computer program SOLAR. The heritabilities of baseline blood pressure were 0.31 for systolic, 0.32 for diastolic, and 0.34 for mean arterial pressure. The heritabilities increased significantly under dietary intervention and were 0.49, 0.49, and 0.51 during low-sodium, 0.47, 0.49, and 0.51 during high-sodium, and 0.51, 0.52, and 0.53 during potassium-supplementation for systolic, diastolic, and mean arterial pressure, respectively. The heritabilities for percentage blood pressure responses to low-sodium were 0.20, 0.21 and 0.23, to high-sodium were 0.22, 0.33, and 0.33, and to potassium-supplementation were 0.24, 0.21, and 0.25, for systolic, diastolic, and mean arterial pressure, respectively. Our study indicated that the heritabilities of blood pressure under controlled dietary sodium and potassium intake were significantly higher than those under usual diet. In addition, the heritabilities of blood pressure responses to dietary sodium and potassium intake were moderate in this study population.