Cyrus Cooper

Bio: Cyrus Cooper is an academic researcher from Southampton General Hospital. The author has contributed to research in topics: Population & Osteoporosis. The author has an hindex of 204, co-authored 1869 publications receiving 206782 citations. Previous affiliations of Cyrus Cooper include University of Oxford & University of York.

Plasma leptin concentration and change in bone density among elderly men and women: the Hertfordshire Cohort Study.

Abstract: Several studies have shown an association between circulating leptin concentration and bone mineral density, but most studies are cross-sectional in design and report findings in women only. We performed a population-based longitudinal study relating baseline plasma leptin concentration to bone mass at the lumbar spine and femoral neck and to change in bone density at these sites over four years in a cohort of 302 men and women aged 60–75 years born and still resident in Hertfordshire, UK. Baseline plasma leptin concentration was strongly positively correlated with body mass index (men: r = 0.71, P < 0.000l; women: r = 0.79, P < 0.0001) and with bone mineral content, bone mineral density, and volumetric bone mineral density at all sites (r = 0.24–0.36, P < 0.001) in both sexes; associations with change in bone density were markedly weaker and inconsistent. Adjustment for adult lifestyle determinants of osteoporosis made little difference to our results, but the associations of leptin with bone mass were no longer significant after adjustment for body mass index. These results suggest that the relationship between plasma leptin and bone mass is similar in men and women and that it is mediated through the strong association of both variables with adiposity, rather than through a direct association of leptin on bone cell function.

Validation of a maternal questionnaire on correlates of physical activity in preschool children.

Abstract: Valid measures of physical activity correlates in preschool children are lacking. This study aimed to assess the validity, factor structure and internal consistency of a maternal questionnaire on potential correlates of four-year-old children's physical activity. The questionnaire was designed to measure the following constructs: child personal factors; parental support and self-efficacy for providing support; parental rules and restrictions; maternal attitudes and perceptions; maternal behaviour; barriers to physical activity; and the home and local environments. Two separate studies were conducted. Study I included 24 mothers of four-year-old children who completed the questionnaire then participated in a telephone interview covering similar items to the questionnaire. To assess validity, the agreement between interview and questionnaire responses was assessed using Cohen's kappa and percentage agreement. Study II involved 398 mothers of four-year-old children participating in the Southampton Women's Survey. In this study, principal components analysis was used to explore the factor structure of the questionnaire to aid future analyses with these data. The internal consistency of the factors identified was assessed using Cronbach's alpha. Kappa scores showed 30% of items to have moderate agreement or above, 23% to have fair agreement and 47% to have slight or poor agreement. However, 89% of items had fair agreement as assessed by percentage agreement (≥ 66%). Limited variation in responses to variables is likely to have contributed to some of the low kappa values. Six questions had a low kappa and low percentage agreement (defined as poor validity); these included questions from the child personal factors, maternal self-efficacy, rules and restrictions, and local environment domains. The principal components analysis identified eleven factors and found several variables to stand alone. Eight of the composite factors identified had acceptable internal consistency (α ≥ 0.60) and three fell just short of achieving this (0.60 > α > 0.50). Overall, this maternal questionnaire had reasonable validity and internal consistency for assessing potential correlates of physical activity in young children. With minor revision, this could be a useful tool for future research in this area. This, in turn, will aid the development of interventions to promote physical activity in this age group.

Clustering of Lifestyle Risk Factors and Poor Physical Function in Older Adults: The Hertfordshire Cohort Study

Abstract: Objectives: To examine the relationship between number of lifestyle risk factors (out of low physical activity, poor diet, obesity, smoking) and physical function in older community-dwelling men and women. Design: Cross-sectional study, Hertfordshire, United Kingdom. Participants: Men (n = 1,682) and women (n = 1,540) aged 59 to 73. Measurements: Physical activity was assessed using an administered questionnaire with a score from 0 to 100; low activity was defined as a score of 50 or less. Diet was assessed using a food frequency questionnaire; diet quality was assessed according to a score for a principal component analysis-defined �healthy� dietary pattern. Poor diet was categorized as a dietary pattern score in the lowest quarter of the distribution. Obesity was defined as a body mass index of 30.0 kg/m2 or more. Physical function was assessed according to self-report (SF-36); poor function was defined as a score in lowest quarter of the distribution. A subgroup of participants had objective assessments of physical function (Timed Up-and-Go Test, timed 3-m walk, chair rises, one-legged standing balance). Results: There was a graded increase in prevalence of poor self-reported physical function in men and women with increasing number of risk factors (men, adjusted odds ratio (AOR) for 3 or 4 risk factors vs none = 3.79, 95% confidence interval (CI) = 2.31�6.21; women, AOR = 5.37, 95% CI = 2.66�10.84). With the exception of balance, the objective assessments also showed graded relationships with number of risk factors, such that more risk factors was associated with poorer physical function. Conclusion: These modifiable lifestyle risk factors are linked to marked differences in risk of poorer physical function in older adults. Efforts to encourage healthy lifestyles have the potential to improve physical function and to promote healthier ageing.

Is lifespan determined in utero

Abstract: Low rates of growth in early life are now known to be associated with an increase in age related disease in later life.1 This is thought to reflect programming, the process whereby a stimulus or insult acting at a critical period of development in early life, has lasting or lifelong importance.2 In animal experiments that have examined the mechanisms responsible for programming, attention has focused on prenatal undernutrition and its influence on gene expression, cell division and differentiation, and tissue structure. Epidemiological studies have shown that markers of poor fetal growth, including low early weight, thinness, and shortness at birth, are associated with increased mortality and morbidity from cardiovascular disease in later life.1 3 Correlations have also been shown between poor early growth and the major cardiovascular risk factors—raised blood pressure,4raised plasma fibrinogen5 and serum cholesterol concentrations,6 impaired glucose tolerance7and reduced arterial compliance.8 These associations were first established by studies in Hertfordshire, where from 1911 to 1948, every newborn baby was weighed and followed up to the age of 1 year. The prevalence of non-insulin diabetes and impaired glucose tolerance, for example, falls threefold between men who weighed 5.5 pounds at birth and those who weighed 9.5 pounds.7 These associations have been replicated in several different countries including the United States9 and India10 as well as in Britain. The associations are independent of adult lifestyle, and are not limited to cardiovascular disease. Chronic obstructive pulmonary disease11 and reduced bone mineral content12 13 are both associated with reduced growth in utero and during infancy. The major determinant of fetal growth is nutrition14-16 and the fetal origins hypothesis proposes that fetal undernutrition programmes the long term adverse sequelae of small size at birth. Cardiovascular disease, impaired …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Using Multivariate Statistics

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Vitamin D Deficiency

Abstract: Once foods in the United States were fortified with vitamin D, rickets appeared to have been conquered, and many considered major health problems from vitamin D deficiency resolved. But vitamin D deficiency is common. This review considers the role of vitamin D in skeletal and nonskeletal health and suggests strategies for the prevention and treatment of vitamin D deficiency.