The association between baroreflex sensitivity and blood pressure in children

Low baroreflex sensitivity (BRS) and heart rate variability (HRV) are associated with the pathogenesis of adult hypertension. However, limited information exists about the negative consequences of elevated childhood blood pressure (BP) and autonomic regulation. Additionally, there are developmental changes in autonomic regulation throughout puberty, yet studies have not appropriately accounted for this. The objective of this study was to investigate BRS and HRV in children with 2 different BP profiles, while controlling for the effects of maturation, age, sex, and body composition. A sample of 11- to 14-year-old participants were divided into 2 BP groups: high BP (HBP; ≥95th percentile; n = 21) and normal BP (NBP; <90th percentile; n = 85). Automated BP was measured at 2 time points. In lab-based testing, 5 min of beat-to-beat BP (Finapres) and R-R interval (RRI) were recorded (standard electrocardiogram) after 15 min of supine rest. Spectral indices were computed using fast Fourier transform, and transfer function analysis was used to compute BRS. High frequency (HF) and low frequency (LF) power spectral areas were set to 0.15-0.4 Hz and 0.04-0.15 Hz, respectively, and BRS was determined for the LF area. After adjustment for age, sex, maturation, and body composition, BRS (p = 0.04), LF (p = 0.008), and HF (p = 0.01) RRI variability, and RRI total power (p = 0.005) were lower in the HBP than in the NBP participants. As well, the LF/HF systolic BP variability ratio was higher in the HBP than in the NBP group (p = 0.03). Despite their young age, these children with high, yet not clinically hypertensive BP, display reduced autonomic regulation.     

Obesity and cardiac autonomic nerve activity in healthy children: Results of the toyama birth cohort study

Objectives To determine the relationship between obesity and cardiac autonomic nerve activity in healthy children. Methods 16 healthy male children comprising of 9 nonobese and 7 obese subjects (body mass index > 19.1 kg/m²) aged 8–9 years were selected. Electrocardiograms were measured for 10 min. under controlled ventilation (0.25 Hz) in the supine position. Consecutive 256-second RR interval data were transformed by the Fast Fourier Transform method into power spectral data. Very low frequency (VLF; 0.003–0.04 Hz), low frequency (LF; 0.04–0.15Hz), high frequency (HF; 0.15–0.40Hz), and total power (TP; 0.003–0.40Hz) were calculated and transformed into a natural logarithm (In). Normalized units (nu) were also calculated as follows: LFnu=LF/(TP-VLF)x100. HFnu=HF/(TP-VLF)x100. Low/high-frequency ratio (LHR) was calculated as LF divided by HF. Unpaired t test was performed to compare the 2 groups. Results TP In and HFnu, reflecting cardiac parasympathetic nerve activity, in obese children were significantly lower than those in nonobese children. In contrast, LFnu and LHF, reflecting cardiac sympathetic nerve activity, in obese children were significantly higher than those in nonobese children. Conclusions These findings suggest that obese children have higher sympathetic nerve activity and lower parasympathetic nerve activity than nonobese children.     

Sympathetic predominance in young male white-collar workers with mild to moderate hypertension

In order to investigate the difference in diurnal variation of autonomic control between young male mild to moderate hypertensive and normotensive white-collar workers, we accessed heart rate variability with ambulatory blood pressure for over 24 hours including work and sleep periods. Both mean systolic and diastolic blood pressures (SBP and DBP) were significantly (p<0.01) higher in hypertensives (HT, n=11) than normotensives (NT, n=11) in all phases, whereas heart rate was not different between them in any phase. Blood pressures during work period (on-duty) were significantly higher than those during non-work period (off-duty) in both NT and HT. High frequency (HF; 0.15-0.40 Hz) power showed a circadian pattern in phase with the sleep-wake cycle. Both HF and low frequency (LF; 0.05-0.15 Hz) powers in HT were significantly lower than that in NT during the sleep period (p<0.05). LF/HF ratio showed a circadian pattern that was almost opposite of the pattern in HF power. Twenty-four-hour average LF/HF in HT was higher than that in NT (p<0.05). Especially during on-duty, LF/HF in HT was significantly higher than in NT (p<0.05). The increase of SBP and LF/HF from off-duty period to on-duty period (deltaSBP and deltaLF/HF) showed significant positive correlation (r=0.67, P<0.05) in HT group, suggesting that the SBP elevation during on-duty in HT may be coupled with sympathetic activation. These results suggest that HT showed significantly reduced parasympathetic control during sleep and an increased sympathetic activity especially during on-duty as compared with NT. Our findings imply that persistence of sympathodominant states together with reduced vagal activity in young mild to moderate hypertensive workers may be related to future cardiovascular disorders.     

Activity of autonomic nervous system is related to body weight in pre-menopausal, but not in post-menopausal women

This study analyzed vegetative modulation, expressed as heart rate variability (HRV) power spectral analysis, in lean and obese women at pre-menopausal or post-menopausal age to reveal possible differences in menopause-related autonomic activity in lean and obese subjects. Sedentary women (n = 40) were divided in four groups: pre-menopausal lean and obese women, post-menopausal lean and obese subjects. The HRV-power spectrum was evaluated on a 5-min long ECG recording. The absolute values of the spectrum were summed in the following frequencies: a low-frequency (0.04-0.15 Hz; LF) and high-frequency (0.15-0.40; HF) range. LF and HF were values used to estimate the sympathetic and parasympathetic activity. LF and HF values of pre-menopausal obese women are lower than values of lean women. The menopause induced a same decrease in LF and HF values in lean and obese subjects, so that no difference was found in post-menopausal groups. This experiment indicates that modifications of autonomic modulation can be included among factors related to obesity in pre-menopausal, but not post-menopausal women.     

Autonomic nervous activity during hand immersion in cold water in patients with vibration-induced white finger

Autonomic nervous function in response to cold was investigated in 21 patients with vibration-induced white finger (VWF) and 17 healthy controls of similar age, using power spectral analysis of heart rate variability. In a supine position, electrocardiogram and skin temperature of both index fingers were measured during immersion of right hand in cold water at 10 degrees C for 10 minutes. Autonomic nervous activity was evaluated from the power of the low-frequency component (LF: 0.02-0.15 Hz), the high-frequency component (HF: 0.15-0.40 Hz) and the ratio of the LF to the HF power (LF/HF ratio). The LF/HF ratio, an index of sympathetic nervous activity, significantly increased during the immersion in the VWF patients, but did not significantly increase in the controls. The LF/HF ratio was then significantly greater in the patients than in the controls during the first 1-2 minutes of the immersion. The HF power related to parasympathetic nervous activity did not change significantly in either group. Finger skin temperature of the immersed right hand was significantly lower in the VWF patients than in the controls during the last five minutes of the immersion and in the recovery period. The present results indicate that sympathetic nervous response to cold is significantly enhanced in VWF patients. The exaggerated sympathetic response to cold in these patients is considered to contribute to the enhanced vasoconstriction of their extremities.     

Waist circumference, body mass index, hip circumference and waist-to-hip ratio as predictors of cardiovascular disease in Aboriginal people

OBJECTIVE: To investigate waist circumference (WC), waist-hip ratio, hip circumference and body mass index (BMI) as risk factors for cardiovascular disease in Aboriginal Australians. METHODS: This cohort study included 836 adults aged 20-74 y in a remote Aboriginal community. WC, waist-hip ratio, hip circumference and BMI were obtained from a screening program. The participants were followed for up to 10 y for cardiovascular events. A Cox regression model was used to calculate the rate ratio (RR) and 95% confidence interval (CI) for the first-ever cardiovascular event (fatal and nonfatal). RESULTS: RRs for the first-ever cardiovascular event were 1.31 (95% CI: 1.11, 1.54), 1.29 (95% CI: 1.09,1.53), 1.28 (95% CI: 1.08, 1.52) and 1.10 (95% CI: 0.93, 1.30) per standard deviation increase in WC, BMI, hip circumference and waist-hip ratio, respectively, after adjustment for diabetes mellitus, total cholesterol, systolic blood pressure and smoking status. WC, BMI and hip circumference were significantly associated with cardiovascular risk, independent of other cardiovascular risk factors. Dividing each of the four parameters into quartiles, WC had the highest likelihood statistics (12.76) followed by BMI (11.45), hip circumference (10.57) and waist-hip ratio (3.15) for predicting first CV events. CONCLUSION: WC, BMI and hip circumference are associated with cardiovascular outcome, independent of traditional risk factors. However, WC appears to be a better predictor for cardiovascular risk than other parameters. Waist-hip ratio is not as useful as other measurements.     

Complex Demodulation of Cardiac Interbeat Intervals: Increased Cardiac Sympathovagal Interaction During Human Sexual Activity

In this study, we analyzed heart rate variability during sexual activity using complex demodulation, which is a useful technique to study continuous changes in different frequency bands over short periods of time. Complex demodulation has the advantage of having higher time resolution compared to spectral analysis. We quantified the low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.5 Hz) amplitudes, and the LF/HF ratio before, during, and after the occurrence of orgasm. LF power is dually mediated by cardiac sympathetic and parasympathetic systems while HF power is mainly influenced by cardiac vagal function. We found a significant increase of cardiac sympathovagal interaction (LF/HF ratios) during the phase of orgasm. These findings are discussed in light of normal sexual physiology and the effect of sex on cardiac autonomic function in patients with heart disease, such as myocardial infarction.     

BMI,Waist Circumference and All-Cause Mortality in a Middle-Aged and Elderly Chinese Population

Objective

To investigate the association of obesity and all-cause mortality in a sample of middle-aged and elderly population.

Design and Setting

Information of participants was collected in the Dongfeng-Tongji study, a perspective cohort study of Chinese occupational population. The main outcome was risk of death after 8.5 years of follow-up.

Participants and measurements

We examined the association of BMI, waist circumference (WC, and waist–height ratio (WHtR) with all-cause mortality in the Dongfeng-Tongji cohort study (n=26,143). Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) for all-cause mortality. Area under the receiver operating characteristic curves and net reclassification improvement (NRI) were used to calculate the power of prediction models.

Results

During a mean of 8.5 years of follow-up, 2,246 deaths were identified. There is a U-shaped association of BMI with all-cause mortality in the middle-aged and elderly Chinese population. Compared with individuals with normal BMI, underweight was positively (HR=2.16, 95% CI: 1.73, 2.69) while overweight (HR=0.75, 95% CI: 0.67, 0.84) and obesity (HR=0.67, 95% CI: 0.56, 0.79) were negatively associated with all-cause mortality after adjustment for potential confounders including WC. In contrast, WC (Q5 vs. Q1, HR=1.55, 95% CI: 1.29, 1.86) and WHtR (Q5 vs.Q1, HR=1.69, 95% CI: 1.40, 2.04) were positively associated with mortality after further adjustment for BMI (P trend < 0.001). Addition of both BMI and WC into the all-cause mortality predictive model significantly increased AUC (P =0.0002) and NRI (NRI = 2.57%, P = 0.0007).

Conclusions

BMI and WC/WHtR were independently associated with all-cause mortality after mutual adjustment. Combination of BMI and WC/WHtR improved the predictive ability of all-cause mortality risk in the middle-aged and elderly population.

     

Obesity in 70-year-old subjects as a risk factor for 15-year coronary heart disease incidence

OBJECTIVE: To investigate the role of obesity in general and waist circumference (WC) and BMI in particular as risk factors for 15-year incidence of coronary heart disease (CHD) in the elderly. RESEARCH METHODS AND PROCEDURES: This prospective study was based on 1597 (737 males and 860 females) 70-year-olds free from CHD and participants of three birth cohorts examined in 1971 to 1972 (Cohort I), 1976 to 1977 (Cohort II), and 1981 to 1982 (Cohort III) at G?teborg, Sweden. Fifteen-year incidence of CHD (fatal and nonfatal) was ascertained from follow-up examinations and registers. Relative risk (RR) for first ever CHD in reference to the lowest quartiles of WC and BMI was calculated from Cox regression. RESULTS: In males, RRs for CHD in the highest WC and BMI quartiles were 1.36 [95% confidence interval (CI) 1.00 to 1.85] and 1.42 (95% CI 1.04 to 1.92), respectively, after adjustment for cohorts, smoking habits, diabetes, systolic blood pressure, and total cholesterol. In men, the risk associated with WC was independent of BMI. Neither WC nor BMI was related to CHD risk in females. After exclusion of first 5-year all-cause deaths, the adjusted RRs in the highest WC and BMI quartiles in males were 1.47 (95% CI 1.06 to 2.04) and 1.42 (1.04 to 1.92), respectively. In females, a significantly higher RR of 1.41 (95% CI 1.02 to 1.94) was observed in the second BMI quartile only after such exclusions. DISCUSSION: WC, an indicator of both central and general obesity, appears to be a stronger predictor of CHD than BMI in elderly males, but in females, obesity was not a risk factor for CHD.     

腰围和体质指数动态变化对高血压发病的影响

目的 探讨腰围(WC)和BMI在2年随访时间内的动态变化对队列人群高血压发病的影响.方法 采用前瞻性研究方法,于2002年1月,对江苏省多代谢异常和代谢综合征(MS)综合防治研究队列人群中随访时间满2年的5888名对象进行第1次随访,完成随访4582名,并于2006年3月对随访时间满5年及参与了第1次随访的对象进行了第2次随访,完成2次随访的对象共3847名,其中满足条件的共2778名基线血压正常对象被纳入分析.基线时WC或BMI正常者在第1次随访时变为非正常者以及基线WC或BMI不正常者在第1次随访时依旧不正常者定义为非控制组;基线WC或BMI非正常者在第1次随访时变为正常以及基线WC或BMI正常者在第1次随访时依旧保持正常者定义为控制组.以第2次随访时是否为高血压作为结局变量(高血压=1,正常血压=0).运用COX比例风险回归模型分析相互调整的WC和BMI差值与高血压发病的关系,以及按照WC和BMI控制与否分层的高血压发病风险,并计算相应的OR和RR值及95％ CI值.结果 2778名研究对象中,新发高血压660例.WC差值和BMI差值以连续型变量进入模型作相巨调整时,男女性中高血压发病与WC差值的关联仍具有统计学意义(男性:OR=1.04,95％ CI:1.01～1.05;女性:OR=1.04,95％CI:1.02 ～1.06),而与BMI差值的关联不再具有统计学意义(男性:OR=1.04,95％CI:0.97～1.11;女性:OR =0.98,95％ CI:0.93～1.03).不论基线WC正常与否,非控制组人群的高血压风险高于控制组人群(基线WC正常组:RR=1.41,95％ CI:1.01～2.39;基线WC非正常组:RR =4.41,95％ CI:1.66 ～9.80).而在基线BMI非正常组中,控制组与非控制组的高血压发病风险差异无统计学意义(RR=1.33,95％ CI:0.88 ～2.02).当WC得到控制,BM1控制与否对高血压发病风险无明显影响(男性:RR=1.03,95％ CI:0.36～2.96;女性:RR =1.02,95％ CI:0.70～5.85),WC未得到控制时,即使BMI得到控制,高血压发病风险仍会明显增加(男性:RR =4.03,95％ CI:1.61～10.09;女性:RR=1.55,95％ CI:1.13 ～3.60).结论 WC和BMI的控制均可降低高血压发病风险,而相比于控制BMI,控制WC对降低高血压风险的效果更好.     

Activity of autonomic nervous system is related to body weight in pre-menopausal,but not in post-menopausal women

Abstract

This study analyzed vegetative modulation, expressed as heart rate variability (HRV) power spectral analysis, in lean and obese women at pre-menopausal or post-menopausal age to reveal possible differences in menopause-related autonomic activity in lean and obese subjects. Sedentary women (n = 40) were divided in four groups: pre-menopausal lean and obese women, post-menopausal lean and obese subjects. The HRV-power spectrum was evaluated on a 5-min long ECG recording. The absolute values of the spectrum were summed in the following frequencies: a low-frequency (0.04–0.15 Hz; LF) and high-frequency (0.15–0.40; HF) range. LF and HF were values used to estimate the sympathetic and parasympathetic activity. LF and HF values of pre-menopausal obese women are lower than values of lean women. The menopause induced a same decrease in LF and HF values in lean and obese subjects, so that no difference was found in post-menopausal groups. This experiment indicates that modifications of autonomic modulation can be included among factors related to obesity in pre-menopausal, but not post-menopausal women.     

Heart rate variability and lifetime risk of cardiovascular disease: the Atherosclerosis Risk in Communities Study

PurposeThe purpose of this study was to estimate the heart rate variability (HRV)–related lifetime cardiovascular disease (CVD) risk.MethodsWe followed 9744 participants without baseline CVD and used a life-table approach to estimate lifetime CVD risk (coronary heart disease, heart failure, and stroke) from 45 through 85 years according to several HRV measures (the SD of RR intervals [SD_NN], the root mean square of successive differences of successive RR intervals, the mean of all normal RR intervals [mean_NN], low-frequency [LF] and high-frequency [HF] power, and the LF/HF ratio).ResultsDuring 192,110 person-years of follow-up, we documented 2856 CVD events. Cox regression analyses with the false discovery rate method correction showed independent associations of SD_NN, mean_NN, LF, and LF/HF in women with CVD. Lifetime CVD risks in the lowest compared with the highest tertile were significantly increased in men for LF/HF (51.3% [95% confidence interval, 47.3–54.7] vs. 43.9% [40.1–47.2]), and in women for SD_NN (39.4% [36.0–43.0] vs. 29.9% [26.3–33.0]), mean_NN (39.3% [35.7–42.7] vs. 28.9% [25.7–31.7]), LF (39.4% [35.9–43.0] vs. 30.0% [26.2–33.2]), and LF/HF (37.6% [33.9–40.9] vs. 30.0% [26.8–32.7]).ConclusionsGreater HRV was modestly associated with lower lifetime CVD risk.     

中国成年人体质指数和腰围与高血压关系的四年随访研究

目的探讨中国成年人体质指数(BMI)和腰围(WC)的增加与高血压发病危险的关系。方法利用“中国居民健康与营养调查”资料,以4552例18~60岁参加2000年调查、当时无高血压等慢性病并且2004年调查被随访到者为研究对象,考察基线BMI和WC对高血压的预测作用,以及BMI和WC4年间的变化与高血压发病之间的关系。结果男性和女性随访4年高血压发病率分别为20.01%和13.52%。随着基线肥胖程度的增加,高血压的发病危险增加。与BMI和WC均不肥胖者相比,BMI超重/肥胖并且WC肥胖者发生高血压的危险最高(男性,RR=2.840,95%CI:2.139~3.771;女性,RR=2.734,95%CI:2.050~3.647)。调整了其它协变量后,4年中BMI每增加一个单位,男性和女性患高血压的危险分别增加0.141和0.109倍;WC每增加1cm,男性和女性患高血压的危险分别增加0.038和0.035倍。结论体质指数和腰围的增加均能增加高血压发病的危险,体质指数和腰围联合使用可增强对高血压发病的预测作用。     

Effects of dinner composition on postprandial macronutrient oxidation in prepubertal girls

OBJECTIVE: To see whether a fat-rich (50%) evening meal promoted fat oxidation and a different spontaneous food intake on the following day at breakfast than a meal with a lower fat content (20%) in 10 prepubertal obese girls. RESEARCH METHODS AND PROCEDURES: The postabsorptive and postprandial (10.5 hours) energy expenditure after a low-fat (LF) (20% fat, 68% carbohydrate, 12% protein) and an isocaloric (2.1 MJ) and isoproteic high-fat (HF; 50% fat, 38% carbohydrate, 12% protein) meal were measured by indirect calorimetry. RESULTS: Fat oxidation was not significantly different after the two meals [LF, 31 +/- 9 vs. HF, 35 +/- 9 g/10.5 hours, p = not significant (NS)]. The girls oxidized 1.8 +/- 0.9 times more fat than that ingested (11.1 grams) with the LF meal vs. 0.3 +/- 0.3 times more fat than that ingested (27.1 grams) with the HF meal (p < 0.001). Carbohydrate oxidation was significantly higher after an LF than an HF meal (39 +/- 12 vs. 29 +/- 9 g/10.5 hours, p < 0,05). At breakfast, the girls spontaneously ingested a similar amount of energy (1.5 +/- 0.7 vs. 1.5 +/- 0.6 MJ, p = NS) and macronutrient proportions (fat, 23% vs. 26%, p = NS; protein, 9% vs. 10%; carbohydrate, 68% vs. 64%,) independently of their having eaten an HF or an LF dinner. DISCUSSION: An HF dinner did not stimulate fat oxidation, and no compensatory effect in spontaneous food intake was observed during breakfast the following morning. Cumulated total fat oxidation after dinner was higher than total fat ingested at dinner, but a much larger negative fat balance was observed after the LF meal. Spontaneous energy and nutrient intakes at breakfast were similar after LF and HF isocaloric, isoproteic dinners. This study points out the lack of sensitivity of short-term fat balance to subsequently readjust fat intake and emphasizes the importance of an LF meal to avoid transient positive fat imbalance.     

Relationship between body mass index, waist circumference, and waist-to-hip ratio and mortality in elderly women: a 5-year follow-up study

This study examines the association between body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC) and all-cause and cardiovascular mortality in elderly women in a 5-year longitudinal study of 575 female outpatients 60 years and over. The highest BMI, WHR, and WC quartiles and predefined BMI categories were analyzed as predictive variables. Death occurred in 88 (15.4%). Underweight (BMI < 18.5 kg/m2) was associated with all-cause mortality in uni- and multivariate analyses, regardless of age bracket. The survival curves and univariate analysis showed that the highest WHR quartile (> or = 0.97) was associated with all-cause mortality. However, after adjustment for age, smoking, and previous cardiovascular diseases, the increase in WHR was positively associated only in women from 60 to 80 years of age. None of the anthropometric measurements was associated with cardiovascular mortality. The results indicate that underweight and increased waist-to-hip ratio were predictors of all-cause mortality in elderly women, mainly among those under 80 years.     

Body mass index, waist circumference, and risk of coronary heart disease: a prospective study among men and women

OBJECTIVE: The purpose of the study was to assess the risk of CHD associated with excess weight measured by BMI and waist circumference (WC) in two large cohorts of men and women. DESIGN, SETTING, SUBJECTS: Participants in two prospective cohort studies, the Health Professionals Follow-up Study (N = 27,859 men; age range 39-75 years) and the Nurses' Health Study (N = 41,534 women; 39-65 years) underwent 16-year follow-up through 2004. RESULTS: 1,823 incident cases of CHD among men and 1,173 cases among women were documented. Compared to men with BMI 18.5 to 22.9 kg/m2, those with a BMI > 30.0 kg/m2 had a multivariate-adjusted RR of CHD of 1.81 (95% CI 1.48 - 2.22). Among women, those with a BMI > 30.0 kg/m2 had a RR of CHD of 2.16 (95% CI 1.81 - 2.58). Compared to men with a WC < 84.0 cm, those with WC of greater than 102.0 cm had a RR of 2.25 (95% CI 1.77 - 2.84). Among women, the RR of CHD was 2.75 (95% CI 2.20 - 3.45) for those with WC of greater than 88.0 cm. CONCLUSIONS: In these analyses from two large ongoing prospective cohort studies, both BMI and WC strongly predicted future risk of CHD. Furthermore, WC thresholds as low as 84.0 cm in men and 71.0 cm in women may be useful in identifying those at increased risk of developing CHD. The findings have broad implications in terms of CHD risk assessment in both clinical practice and epidemiologic studies.     

Association between Dietary Inflammatory Index,Dietary Patterns,Plant-Based Dietary Index and the Risk of Obesity

Evidence on the association between various dietary constructs and obesity risk is limited. This study aims to investigate the longitudinal relationship between different diet indices and dietary patterns with the risk of obesity. Non-obese participants (n = 787) in the North West Adelaide Health Study were followed from 2010 to 2015. The dietary inflammatory index (DII^®), plant-based dietary index (PDI) and factor-derived dietary pattern scores were computed based on food frequency questionnaire data. We found the incidence of obesity was 7.62% at the 5-year follow up. In the adjusted model, results from multivariable log-binomial logistic regression showed that a prudent dietary pattern (RR_Q5 vs. _Q1 = 0.38; 95% CI: 0.15–0.96), healthy PDI (RR = 0.31; 95% CI: 0.12–0.77) and overall PDI (RR = 0.56; 95% CI: 0.23–1.33) were inversely associated with obesity risk. Conversely, the DII (RR = 1.59; 95% CI: 0.72–3.50), a Western dietary pattern (RR = 2.16; 95% CI: 0.76–6.08) and unhealthy PDI (RR = 1.94; 95% CI: 0.81–4.66) were associated with increased risk of obesity. Based on the cubic spline analysis, the association between an unhealthy PDI or diet quality with the risk of obesity was non-linear. In conclusion, an anti-inflammatory diet, healthy diet or consumption of healthy plant-based foods were all associated with a lower risk of developing obesity.     

Body Mass Index,Waist-circumference and Cardiovascular Disease Risk Factors in Iranian Adults: Isfahan Healthy Heart Program

Considering the main effect of obesity on chronic non-communicable diseases, this study was performed to assess the association between body mass index (BMI), waist-circumference (WC), cardiometabolic risk factors and to corroborate whether either or both BMI and WC are independently associated with the risk factors in a sample of Iranian adults. This cross-sectional study was performed on data from baseline survey of Isfahan Healthy Heart Program (IHHP). The study was done on 12,514 randomly-selected adults in Isfahan, Najafabad and Arak counties in 2000-2001. Ages of the subjects were recorded. Fasting blood glucose (FBG), 2-hour post-load glucose (2hpp), serum lipids, systolic and diastolic blood pressure (SBP and DBP), BMI, WC, smoking status, and total daily physical activity were determined. Increase in BMI and WC had a significant positive relation with the mean of FBG, 2hpp, SBP, DBP, serum lipids, except for HDL-C (p<0.001 for all). After adjustment for age, smoking, physical activity, socioeconomic status (SES), and BMI, the highest odds ratio (OR) (95% CI) for diabetes mellitus (DM) according to WC was 3.13 (1.93-5.08) and 1.99 (1.15-3.44) in women and men respectively. Moreover, the highest ORs based on BMI with adjustment for age, smoking, physical activity, SES, and WC were for dyslipidaemia (DLP) [1.97 (1.58-2.45) in women and 2.96 (2.41-3.63) in men]. The use of BMI or WC alone in the models caused to enhance all ORs. When both BMI and WC were entered in the model, the ORs for all risk factors, in men, according to BMI, were more compared to WC. However, in women, ORs for DM and hypertension (HTN) in WC quartiles were more than in BMI quartiles. BMI is the better predictor of DM, HTN, and DLP in men compared to WC. Conversely, in women, WC is a superior predictor than BMI, particularly for DM and HTN. Furthermore, the measurement of both WC and BMI in Iranian adults may be a better predictor of traditional risk factors of CVDs compared to BMI or WC alone.Key words: Body mass index, Diabetes mellitus, Dyslipidaemia, Hypertension, Obesity, Risk Factor, Waist-circumference, Iran     

依托咪酯或丙泊酚对老年冠心病非心脏手术围插管期心率变异性的影响

目的 研究依托咪酯和丙泊酚对老年冠心病患者行非心脏手术时在全身麻醉诱导气管插管期间心率变异性(HRV)的影响.方法将90例择期行中上腹部手术的老年冠心病患者随机分成依托咪酯组(E组)和丙泊酚组(P组),每组各45例.分别于麻醉前、麻醉诱导后及气管插管后用心率变异功率谱分析技术观察两组患者的HRV变化.结果麻醉诱导后,E组总功率(TP)和HRV低频(LF)[(756±535)ms2/Hz和(316±301)ms2/Hz],P组LF、HRV高频(HF)、LF/HF及TP[(187±168)ms2/Hz、(89±48)ms2/Hz、2.3±1.6和(616±462)ms2/Hz]均较麻醉前显著降低(P<0.05);组间比较,麻醉诱导后,E组LF、HF、LF/HF及TP均显著高于P组(P<0.05).气管插管后,两组LF、HF、LF/HF及TP均较麻醉前显著升高(P<0.05);组间比较,气管插管后两组HRV各指标比较差异均无统计学意义(P>0.05).结论丙泊酚在麻醉诱导时对老年冠心病自主神经功能的抑制作用强于依托咪酯;而对于气管插管引起的心血管反应而言依托咪酯和丙泊酚药效相似.     

心率变异性在脑力负荷评价中的应用

目的探讨用心率变异性(HRV)来评价脑力负荷的可行性。方法受试者在计算机前输入随机数字,模拟脑力劳动。采用Holter8800型动态心电图分析仪连续记录其心电信号,并将心电信号转变为数字信号,应用Holter分析软件分析HRV频域指标:总功率(TP)、低频(LF)、高频(HF)、LFHF。结果输入数字的速度随时间的延长而逐渐增加,输入正确率却逐渐下降。输入速度与HRV的TP和LF呈明显的正相关(r值分别为0.851和0.827,P<0.05),并呈现剂量-反应关系,而HF和LFHF与输入速度之间没有明显相关。休息和脑力劳动开始时HRV各指标的值分别为:TP:(2745.4±1301.6)、(686.2±420.7)ms2Hz;HF:(670.6±393.8)、(202.6±171.7)ms2Hz;LF:(870.5±553.7)、(206.0±187.9)ms2Hz。脑力劳动时HRV各指标与休息时相比,均明显降低,这是一个总的趋势。然后它们在低水平上随着负荷量(强度和时间)的增加而波动且有逐渐升高的趋势。结论心率变异性可以用作脑力劳动负荷的评价指标,但其变化规律有待于进一步的研究。