The obesity paradox in men with coronary heart disease and heart failure: The role of muscle mass and leptin

Aims

We have investigated the role of muscle mass, natriuretic peptides and adipokines in explaining the obesity paradox.

Background

The obesity paradox relates to the association between obesity and increased survival in patients with coronary heart disease (CHD) or heart failure (HF).

Methods

Prospective study of 4046 men aged 60–79 years followed up for a mean period of 11 years, during which 1340 deaths occurred. The men were divided according to the presence of doctor diagnosed CHD and HF: (i) no CHD or HF ii), with CHD (no HF) and (iii) with HF.

Results

Overweight (BMI 25–9.9 kg/m²) and obesity (BMI ≥ 30 kg/m²) were associated with lower mortality risk compared to men with normal weight (BMI 18.5–24.9 kg/m²) in those with CHD [hazards ratio (HR) 0.71 (0.56,0.91) and 0.77 (0.57,1.04); p = 0.04 for trend] and in those with HF [HR 0.57 (0.28,1.16) and 0.41 (0.16,1.09; p = 0.04 for trend). Adjustment for muscle mass and NT-proBNP attenuated the inverse association in those with CHD (no HF) [HR 0.78 (0.61,1.01) and 0.96 (0.68,1.36) p = 0.60 for trend) but made minor differences to those with HF [p = 0.05]. Leptin related positively to mortality in men without HF but inversely to mortality in those with HF; adjustment for leptin abolished the BMI mortality association in men with HF [HR 0.82 (0.31,2.20) and 0.99 (0.27,3.71); p = 0.98 for trend].

Conclusion

The lower mortality risk associated with excess weight in men with CHD without HF may be due to higher muscle mass. In men with HF, leptin (possibly reflecting cachexia) explain the inverse association.     

血管紧张素原基因5’端启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性

目的:分析血管紧张素原基因启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性。方法:实验于2005-08/2006-01在北京华大实验室完成。选取对象均为生活在内蒙古乌拉特后旗的蒙古族牧民,三代血亲内无其他民族。采用基因测序技术对内蒙古蒙古族人群中107例原发性高血压患者和108例正常对照者进行A-20C和A-6G基因分型,观察高血压组和正常对照组不同基因型的分布和等位基因频率的差异。结果:①两组受试者在性别、年龄及吸烟、饮酒、体质量指数和临床化验检查指标有较好的匹配(P均>0.05)。②两组血管紧张素原基因A-20C位点AA,AC,CC基因型频率比较差异无显著性意义(高血压组分别为0.51,0.29,0.20;正常对照组分别为0.49,0.28,0.23,χ2=0.395,P=0.529)。A,C等位基因频率比较差异无显著性意义(高血压组分别为0.65,0.35;正常对照组分别为0.63,0.37,χ2=0.015,P=0.904)。③两组血管紧张素原基因A-6G位点AA,AG,GG基因型频率比较差异无显著性意义(高血压组分别为0.50,0.33,0.17;正常对照组分别为0.55,0.34,0.11,χ2=1.924,P=0.165)。A,G等位基因频率比较差异无显著性意义(高血压组分别为0.66,0.34;正常对照组分别为0.72,0.28,χ2=1.728,P=0.189)。④高血压组协同存在血管紧张素原基因A-20C基因型CC时,血管紧张素原基因A-6G基因型GG频率稍高于正常对照组,但差异无显著性意义(χ2=2.395,P=0.122,OR=7.52,95%CI0.014～1.250),高血压组G等位基因明显高于正常对照组(分别为0.37,0.22,χ2=4.658,P=0.034),携带该等位基因的蒙古族人群发生原发性高血压的相对危险度升高(OR=2.80,95%CI1.087～7.271)。结论:血管紧张素原基因A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压相关,并可能具有协同作用。     

Physical activity, metabolic factors, and the incidence of coronary heart disease and type 2 diabetes

OBJECTIVE: To examine the role of nonfasting serum insulin level and components of the insulin resistance syndrome in the relationship between physical activity and the incidence of coronary heart disease and type 2 diabetes. METHODS: Prospective study of 5159 men aged 40 to 59 years with no history of coronary heart disease, type 2 diabetes, or stroke drawn from general practices in 18 British towns. During an average follow-up period of 16.8 years, there were 616 cases of major coronary heart disease events (fatal and nonfatal) and 196 incident cases of type 2 diabetes. RESULTS: After adjustment for potential confounders (lifestyle characteristics and preexisting disease), physical activity was inversely related to coronary heart disease rates, with the lowest rates in the men undertaking moderate physical activity and with no further benefit thereafter. For type 2 diabetes, risk decreased progressively with increasing levels of physical activity. Physical activity was associated with serum insulin level and with factors associated with insulin, ie, heart rate, hyperuricemia, diastolic blood pressure, and high-density lipoprotein cholesterol level, and with gamma-glutamyltransferase level, a possible marker of hepatic insulin resistance. Adjustment for insulin and associated factors made little difference to the relationship between physical activity and risk of coronary heart disease. By contrast, these factors together with gamma-glutamyltransferase level appear to explain a large proportion of the reduction in risk of type 2 diabetes associated with physical activity. CONCLUSIONS: The relationship between physical activity and type 2 diabetes appears to be mediated by serum true insulin level and components of the insulin resistance syndrome. However, these factors do not appear to explain the inverse relationship between physical activity and coronary heart disease.     

Atrial natriuretic peptide in the preterm infant. Lack of correlation with natriuresis and diuresis

We assessed the relation of atrial natriuretic peptide (ANP) to renal function on postnatal day 2 and day 5 in preterm infants. Plasma ANP concentration was measured by radioimmunoassay in two groups of preterm infants: group 1, gestational age less than 30 weeks, n = 10; and group 2, gestational age 30-34 weeks, n = 11. The identity of the immunoreactivity as ANP-28 was confirmed by HPLC. Plasma ANP was significantly higher in group 1 than in group 2 on day 2 and day 5 (p < 0.01) and ANP concentration decreased by day 5 in both groups (group 1, p < 0.01; group 2, p < 0.02). The results showed no correlation between plasma ANP concentration and urinary sodium excretion or creatinine clearance, which may be due to a blunted renal response to ANP, but other factors may be involved also. We conclude that preterm infants are able to release large amounts of ANP, but a high plasma ANP concentration does not correlate directly with renal regulation of sodium and water balance.     

Impact of a medically supervised safer injecting facility on drug dealing and other drug-related crime

North America's first medically supervised safer injecting facility (SIF) recently opened in Vancouver, Canada. One of the concerns prior to the SIF's opening was that the facility might lead to a migration of drug activity and an increase in drug-related crime. Therefore, we examined crime rates in the neighborhood where the SIF is located in the year before versus the year after the SIF opened. No increases were seen with respect to drug trafficking (124 vs. 116) or assaults/robbery (174 vs. 180), although a decline in vehicle break-ins/vehicle theft was observed (302 vs. 227). The SIF was not associated with increased drug trafficking or crimes commonly linked to drug use.     

HIV seroprevalence among participants at a Supervised Injection Facility in Vancouver, Canada: implications for prevention, care and treatment

North America's first government sanctioned medically supervised injection facility (SIF) was opened during September 2003 in Vancouver, Canada. This was in response to a large open public drug scene, high rates of HIV and hepatitis C transmission, fatal drug overdoses, and poor health outcomes among the city's injection drug users. Between December 2003 and April 2005, a representative sample of 1,035 SIF participants were enrolled in a prospective cohort that required completing an interviewer-administered questionnaire and providing a blood sample for HIV testing. HIV infection was detected in 170/1007 (17%) participants and was associated with Aboriginal ethnicity (adjusted Odds Ratio [aOR], 2.70, 95% Confidence Interval [95% CI], 1.84–3.97), a history of borrowing used needles/syringes (aOR, 2.0, 95% CI, 1.37–2.93), previous incarceration (aOR, 1.87, 95% CI, 1.11–3.14), and daily injection cocaine use (aOR, 1.42, 95% CI, 1.00–2.03). The SIF has attracted a large number of marginalized injection drug users and presents an excellent opportunity to enhance HIV prevention through education, the provision of sterile injecting equipment, and a supervised environment to self-inject. In addition, the SIF is an important point of contact for HIV positive individuals who may not be participating in HIV care and treatment.     

曲安奈德辅助玻璃体切割术的应用

目的研究曲安奈德（TA）辅助玻璃体切割手术在临床的应用价值。方法28例（29只眼）于2004年1月～2004年12月行玻璃体切割术，术中注入已过滤的TA悬浮液0．1ml（40mg／m1），以帮助辨认玻璃体后皮质、视网膜前增殖膜、黄斑前膜、内界膜，9例硅油填充，7例C3FR（15％）填充。手术后17例随访6个月以上，11例随访3至4个月。结果所有的病例，经TA注入后，可明显的改善玻璃体后皮质、视网膜前膜、内界膜的辨认情况。糖尿病视网膜病变术后视力提高占61．5％，伴PVR的视网膜脱离术后视力提高占61．3％，黄斑裂孔4例中3例术后视力提高，4例黄斑前膜术后视力均有提高。所有28例均没有出现高眼压。8例伴PVR的视网膜脱离中6例（占75％）视网膜复位，4例黄斑裂孔均关闭，2例糖尿病黄斑水肿手术后明显减轻。结论经过滤的TA可作为玻璃体切割手术中较好的辅助工具，TA悬浮液是呈白色胶样，可粘附于玻璃体皮质、视网膜前膜或内界膜，帮助分辨玻璃体后皮质、视网膜前膜、内界膜，提高手术效率。没有发现与TA有关的副作用。