城市化的生态风险及其管理

城市化体现在人口向城市聚集和城市景观扩张的同时,社会结构发生了极大变化,城市生产生活方式向更加广泛的地区扩散。然而,随着人口的过度密集和城市的日益扩张,交通拥堵、空气污染、废物堆积、流行病肆虐等"城市病"频发。城市通过大量汲取和消耗自然资源,向周围环境排放大量污染物,改变了区域生态系统的原有结构和功能,产生了严峻的生态风险,进而制约着城市生态系统的可持续发展。城市化的生态风险正逐步得到广泛关注,但对其具体的内涵和影响尚不明晰。归类描述了城市化过程中面临的各种生态风险,分析了导致生态风险的主要因素,阐述了辨识与评价生态风险的基本方法,提出了城市化生态风险的调控管理对策。     

Offspring risk and sibling risk for multilocus traits

The recurrence risk of a trait in a relative of type R is the probability that an individual who is in relationship of type R to an affected proband has the trait. It is intuitively clear that closer relationships lead to higher recurrence risks. However, no exact analysis of this phenomenon has been presented for multilocus traits. We prove a theorem that shows how recurrence risks are influenced by the degree of closeness of the relationship R. For example, our theorem implies that sibling risk is always higher than offspring risk. The loci influencing the trait are assumed to be autosomal and unlinked, but arbitrary epistasis between the loci is allowed. We give a detailed proof of the theorem by using stochastic matrices. A shorter proof based on the additive and dominance genetic variances is also sketched. Additionally, we also give some empirical results and discuss generalizations of the theorem.     

Atherosclerosis risk factors in children of high risk families

The Objective of this study was to determine the frequency of care reactive atherosclerosis risk factors in children of parents with premature coronary heart disease observed before their 45 years of age for the promotion of the effectivity of the preventive work started in childhood and adolescent ages. METHODS: Height and weight was measured. Body mass index (BMI) was calculated. Fat analysis was performed in children with overweight. Blood pressure was measured and both 24 hour monitoring and fundoscopy were performed in cases with a blood pressure higher than 90 centile values. Fasting blood sugar (BS) level was measured. Oral glucose tolerance test was made in cases with a fasting BS level higher than 5 mmol/l. Serum total cholesterol (TC), HDL-cholesterol (HDLC) and total triglyceride (TT) levels were measured and LDL-cholesterol (LDLC) level was calculated. The plasma thiobarbituric acid reactive system (TBARS) was investigated. Statistical analyses were performed by chi2 and Student t-probes. Data of 1140 offsprings and 457 referents without any high atherosclerotic risk family history were analyzed. RESULTS: BMI of 87 offsprings was higher than the 90 centile value. The fat percent of the body of these children was higher than 40. The blood pressure of 311 children and adolescents was higher than the 90 centile value. Fasting BS level was higher than 5 mmol/l in 47 cases 17 of them showed a pathologic oral glucose tolerance test. High serum TC level was observed in 67 cases, high serum TT level was found in 8 cases. 245 offsprings had a low serum HDLC level. The plasma TBARS level was high in 241 cases. Data of referents differed significantly from those of offsprings. Their serum TC, LDLC levels and plasma TBARS level were lower, serum HDLC level was higher than that of children and adolescents with high risk atherosclerotic family history. CONCLUSION: Risk factors of atherosclerosis are detectable in children and adolescents of high risk families. The measurement of these factors may help the efficacy of the preventive work.     

C-reactive protein as a risk factor versus risk marker

PURPOSE OF REVIEW: C-reactive protein (CRP) is consistently associated with cardiovascular disease in prospective and cross-sectional clinical and epidemiological studies. Inflammation is an important mechanism in cardiovascular disease, and the plasma level of CRP is considered to reflect the inflammatory condition of the patient and/or the vessel wall. In addition, there are also a number of indications for a causal role of CRP in cardiovascular disease. RECENT FINDINGS: A number of new publications show potential causal effects of CRP on cardiovascular disease, and evidence from human-CRP transgenic animals also indicates a causal contribution of CRP to cardiovascular disease. On the other hand, a new large prospective study and an updated meta-analysis indicate that the contribution of CRP to cardiovascular disease is less impressive than reported earlier (odds ratio, 1.58; 95% confidence interval, 1.48-1.68). SUMMARY: We review here the most recent evidence on mechanisms by which CRP is involved as a causal factor in the precipitation of cardiovascular disease. Evidence for such a role is accumulating.     

Defining reducible risk

In maternity care, costly high-technology interventions that have never been shown to be clinically effective continue to be used in the United States, while inexpensive and effective low-technology interventions continue to be underused. Three high-technology approaches to risk reduction—electronic fetal monitoring, cesarean section, and home uterine activity monitoring are contrasted with three low-technology approaches—prenatal care, smoking cessation, and nutrition supplementation. These technologies are examined in terms of current controversies over their safety, efficacy, and cost-effectiveness. Examination of these controversies illustrates how the medical technology industry, the regulatory process, and systems of social stratification contribute to social and cultural constructions of what are regarded as reducible birth risks.     

Discordant risk: Overweight and cardiometabolic risk in Chinese adults

Objective:

Recent US work identified “metabolically healthy overweight” and “metabolically at risk normal weight” individuals. Less is known for modernizing countries with recent increased obesity.

Design and Methods:

Fasting blood samples, anthropometry and blood pressure from 8,233 adults aged 18‐98 in the 2009 nationwide China Health and Nutrition Survey, were used to determine prevalence of overweight (Asian cut point, BMI ≥23 kg/m²) and five risk factors (prediabetes/diabetes (hemoglobin A1c ≥5.7%) inflammation (high‐sensitivity C‐reactive protein (hsCRP) ≥3 mg/l), prehypertension/hypertension (Systolic blood pressure/diastolic blood pressure≥130/85 mm Hg), high triglycerides (≥150 mg/dl), low high‐density lipoprotein cholesterol (<40 (men)/ <50 mg/dl (women)). Sex‐stratified, logistic, and multinomial logistic regression models estimated concurrent obesity and cardiometabolic risk, with and without abdominal obesity, adjusting for age, smoking, alcohol consumption, physical activity, urbanicity, and income.

Results:

Irrespective of urbanicity, 78.3% of the sample had ≥1 elevated cardiometabolic risk factor (normal weight: 33.2% had ≥1 elevated risk factor; overweight: 5.7% had none). At the age of 18‐30 years, 47.4% had no elevated risk factors, which dropped to 6% by the age 70, largely due to age‐related increase in hypertension risk (18‐30 years: 11%; >70 years: 73%). Abdominal obesity was highly predictive of metabolic risk, irrespective of overweight (e.g., “metabolically at risk overweight” relative to “metabolically healthy normal weight” (men: relative risk ratio (RRR) = 39.06; 95% confidence interval (CI): 23.47, 65.00; women: RRR = 22.26; 95% CI: 17.49, 28.33)).

Conclusion:

A large proportion of Chinese adults have metabolic abnormalities. High hypertension risk with age, underlies the low prevalence of metabolically healthy overweight. Screening for cardiometabolic‐related outcomes dependent upon overweight will likely miss a large portion of the Chinese at risk population.