ACTN3 genotype, athletic status, and life course physical capability: meta-analysis of the published literature and findings from nine studies

The ACTN3 R577X (rs1815739) genotype has been associated with athletic status and muscle phenotypes, although not consistently. Our objective was to conduct a meta-analysis of the published literature on athletic status and investigate its associations with physical capability in several new population-based studies. Relevant data were extracted from studies in the literature, comparing genotype frequencies between controls and sprint/power and endurance athletes. For life course physical capability, data were used from two studies of adolescents and seven studies in the Healthy Ageing across the Life Course (HALCyon) collaborative research program, involving individuals aged between 53 and 90+ years. We found evidence from the published literature to support the hypothesis that in Europeans the RR genotype is more common among sprint/power athletes compared with their controls. There is currently no evidence that the X allele is advantageous to endurance athleticism. We found no association between R577X and grip strength (P = 0.09, n = 7,672 in males; P = 0.90, n = 7,839 in females), standing balance, timed get up and go, or chair rises in our studies of physical capability. The ACTN3 R577X genotype is associated with sprint/power athletic status in Europeans, but does not appear to be associated with objective measures of physical capability in the general population. Hum Mutat 32:1–11, 2011. © 2011 Wiley-Liss, Inc.

Pre-natal and post-natal growth trajectories and childhood cognitive ability and mental health

BACKGROUND

Most studies of the associations between pre-natal or post-natal growth and cognitive ability have been based on children with pathologically slow growth measured between two time points only, rather than children with normal growth trajectories estimated from multiple measures of growth.

METHODS

We investigated the associations of pre-natal and post-natal trajectories in both weight and length/height through the first 5 years of life with cognitive ability and mental health at 6.5 years of age among healthy children. Our study is based on 11 899 children who were born healthy at ≥37 completed weeks with birth weight ≥2500 g and had up to 13 measures of weight and length/height from birth to age 5 years and cognitive ability and behaviour measured at 6.5 years. Using a linear spline random-effects model with 2 knots at 3 and 12 months, we estimated growth trajectories for each child from birth to age 5 years in weight and length/height in four periods: gestational age-specific birth weight and length (pre-natal 'growth'), early infancy (0-3 months), late infancy (3-12 months) and early childhood (1-5 years). We used generalized estimating equations to estimate mean differences in IQ and mental health according to pre-natal and post-natal growth trajectory. IQ was measured using the Wechsler Abbreviated Scales of Intelligence, and mental health was assessed using the Strengths and Difficulties Questionnaire.

RESULTS

A 1 standard deviation (SD) in birth weight was positively associated with cognitive ability (0.82 IQ points, 95% CI: 0.54-1.10) after adjusting for confounders. For post-natal weight gain trajectories, a 1 SD faster weight gain was associated with an increase of 0.77 (95% CI: 0.42-1.11) IQ points for early infancy, 0.30 (95% CI: 0.02-0.58) points for late infancy, and 0.40 (95% CI: 0.04-0.76) for early childhood after adjusting for confounders and for earlier growth. For length/height trajectories, the magnitudes of increase in cognitive ability were similar to each other (~0.6 points) across the four periods. Pre-natal and infancy growth, but not early childhood growth, were associated with reduced externalising behaviours.

CONCLUSIONS

Although the effect sizes are small and residual confounding cannot be excluded, our results suggest that among healthy children, faster growth from the pre-natal period through age 5 years is positively associated with cognitive ability, whereas faster growth in the pre-natal period and infancy is positively associated with mental health at early school age.

Association between urban life-years and cardiometabolic risk: the Indian migration study

Urban living is associated with an increase in cardiometabolic risks, but the speed at which these risks are accrued over time is unknown. Using a cross-sectional sibling-pair design, the authors surveyed migrant factory workers and their spouses from 4 cities in India together with their rural-dwelling siblings and examined the associations between urban life-years and cardiometabolic risk factors. Data on 4,221 participants (39% women; mean age = 41 years) were available (2005-2007). In regression models, a 2-slope pattern for body fat (with a marked shift at 10 years) was found, whereas a common slope could be accepted for other risk factors. In men, the regression coefficients (per decade of urban life) were 2.5% in the first decade and 0.1% thereafter for body fat; 1.4 mm Hg for systolic blood pressure; and 7% for fasting insulin. Age, gender, marital status, household structure, and occupation did not influence the patterns appreciably; however, stronger gradients for adiposity were noted in migrants from lower socioeconomic positions. The findings suggest that body fat increases rapidly when one first moves to an urban environment, whereas other cardiometabolic risk factors evolve gradually. Public health interventions focused on the control of obesity in newer migrants to urban areas, particularly those from lower socioeconomic positions, may be beneficial.

The 'centre effect' in nephrology: what do differences between nephrology centres tell us about clinical performance in patient management?

Improving the quality of care provided by nephrology centres to patients with kidney disease requires a clear understanding of how to compare performance after adjustment for case mix, combined with a detailed understanding of the structure and processes that are associated with the achievement of good clinical results. In this review, we discuss how to measure quality of care (using process or outcome measures), how to take case mix into account, how best to display comparisons between nephrology centres, and how to study the causes of real variations in quality between centres. This is a narrative review; we include examples from other fields in which the centre effect has been studied, including education.

Absence of association of a single-nucleotide polymorphism in the TERT-CLPTM1L locus with age-related phenotypes in a large multicohort study: the HALCyon programme

Several age-related traits are associated with shorter telomeres, the structures that cap the end of linear chromosomes. A common polymorphism near the telomere maintenance gene TERT has been associated with several cancers, but relationships with other aging traits such as physical capability have not been reported. As part of the Healthy Ageing across the Life Course (HALCyon) collaborative research programme, men and women aged between 44 and 90 years from nine UK cohorts were genotyped for the single-nucleotide polymorphism (SNP) rs401681. We then investigated relationships between the SNP and 30 age-related phenotypes, including cognitive and physical capability, blood lipid levels and lung function, pooling within-study genotypic effects in meta-analyses. No significant associations were found between the SNP and any of the cognitive performance tests (e.g. pooled beta per T allele for word recall z-score = 0.02, 95% CI: -0.01 to 0.04, P-value = 0.12, n = 18,737), physical performance tests (e.g. pooled beta for grip strength = -0.02, 95% CI: -0.045 to 0.006, P-value = 0.14, n = 11,711), blood pressure, lung function or blood test measures. Similarly, no differences in observations were found when considering follow-up measures of cognitive or physical performance after adjusting for its measure at an earlier assessment. The lack of associations between SNP rs401681 and a wide range of age-related phenotypes investigated in this large multicohort study suggests that while this SNP may be associated with cancer, it is not an important contributor to other markers of aging.

Life course trajectories of systolic blood pressure using longitudinal data from eight UK cohorts

BACKGROUND

Much of our understanding of the age-related progression of systolic blood pressure (SBP) comes from cross-sectional data, which do not directly capture within-individual change. We estimated life course trajectories of SBP using longitudinal data from seven population-based cohorts and one predominantly white collar occupational cohort, each from the United Kingdom and with data covering different but overlapping age periods.

METHODS AND FINDINGS

Data are from 30,372 individuals and comprise 102,583 SBP observations spanning from age 7 to 80+y. Multilevel models were fitted to each cohort. Four life course phases were evident in both sexes: a rapid increase in SBP coinciding with peak adolescent growth, a more gentle increase in early adulthood, a midlife acceleration beginning in the fourth decade, and a period of deceleration in late adulthood where increases in SBP slowed and SBP eventually declined. These phases were still present, although at lower levels, after adjusting for increases in body mass index though adulthood. The deceleration and decline in old age was less evident after excluding individuals who had taken antihypertensive medication. Compared to the population-based cohorts, the occupational cohort had a lower mean SBP, a shallower annual increase in midlife, and a later midlife acceleration. The maximum sex difference was found at age 26 (+8.2 mm Hg higher in men, 95% CI: 6.7, 9.8); women then experienced steeper rises and caught up by the seventh decade.

CONCLUSIONS

Our investigation shows a general pattern of SBP progression from childhood in the UK, and suggests possible differences in this pattern during adulthood between a general population and an occupational population. Please see later in the article for the Editors' Summary.

Is relative leg length a biomarker of childhood nutrition? Long-term follow-up of the Hyderabad Nutrition Trial

BACKGROUND

Relative leg length is frequently used as a biomarker of childhood nutrition in epidemiological studies, but evidence is lacking. We examined the association between supplemental nutrition in pregnancy and childhood and relative proportions of components of height in adolescence.

METHODS

In a community trial of nutritional supplementation, villages from adjacent administrative areas were selected to serve as intervention (n = 15) and control (n = 14) arms. In the intervention villages, balanced protein-calorie supplementation (2.51 MJ, 20 g protein) was offered daily to pregnant women and their offspring until the age of 6 years. Children born in the trial were re-examined 15 years later to assess components of height.

RESULTS

A total of 1165 adolescents (intervention: 654, 49% of trial participants; control: 511, 41% of trial participants) aged 13-18 years were examined. Supplemented children were 10 mm taller [95% confidence interval (CI): 1.4 to 18.7 mm], but almost all of the increase was in trunk length (9 mm, 95% CI: 2.6 to 15.4 mm). The age- and gender-adjusted β-coefficients for the association of nutritional supplementation with relative trunk, leg and lower leg lengths (expressed as standard deviation scores) were 0.26 (95% CI: 0.11 to 0.42), 0.08 (95% CI: -0.03 to 0.19) and 0.03 (95% CI: -0.08 to 0.15) respectively, thereby unsupportive of cephalocaudal gradient in growth.

CONCLUSIONS

In this nutritional supplementation trial in an undernourished population, we were unable to confirm relative leg length as a biomarker of childhood nutrition. Alternative explanations may underlie the reported associations between childhood conditions and relative leg length.

The prevalence and analysis of risk factors for age-related macular degeneration: 18-year follow-up data from the Speedwell eye study, United Kingdom

AIMS/PURPOSE

To determine the prevalence of age-related maculopathy (ARM) and age-related macular degeneration (AMD) in men aged 65-83 years living in the Speedwell region of Bristol, United Kingdom and identify modifiable risk factors.

METHODS

A total of 2348 men recruited to the Speedwell prospective cohort study in 1979 were followed up in 1997 with an eye questionnaire and had retinal photographs that were assessed using the International Classification System for ARM.

RESULTS

In all, 934 men (66.8% response rate) attended with a mean of 17.9 years (15.3-20.6 years) follow-up. Early ARM (grades 2-3) was found in 9.2% (95% confidence interval (CI) 7.4%, 11.4%) and late age-related maculopathy (grade 4, AMD) in 0.5% (95% CI 0.2%, 1.2%). The risk of ARM (grades 2-4) was increased with raised C-reactive protein and consumption of lard and solid fats, whereas triglyceride levels were associated with a lower risk. The latter were confirmed in multivariable analyses and in addition, haemodynamic measures also predicted risk (eg mean arterial pressure odds ratio (OR) per z-score 1.37, 95% CI 1.04, 1.79).

CONCLUSIONS

In a representative cohort of men aged 65-83 from Bristol, United Kingdom, many had macular changes that put them at higher risk of developing AMD. Various modifiable exposures were associated with an increased risk ARM/AMD. Opportunities for screening and undertaking secondary prevention interventions need to be explored to prevent progression of the disease and blindness.

Association between common variation at the FTO locus and changes in body mass index from infancy to late childhood: the complex nature of genetic association through growth and development

An age-dependent association between variation at the FTO locus and BMI in children has been suggested. We meta-analyzed associations between the FTO locus (rs9939609) and BMI in samples, aged from early infancy to 13 years, from 8 cohorts of European ancestry. We found a positive association between additional minor (A) alleles and BMI from 5.5 years onwards, but an inverse association below age 2.5 years. Modelling median BMI curves for each genotype using the LMS method, we found that carriers of minor alleles showed lower BMI in infancy, earlier adiposity rebound (AR), and higher BMI later in childhood. Differences by allele were consistent with two independent processes: earlier AR equivalent to accelerating developmental age by 2.37% (95% CI 1.87, 2.87, p = 10(-20)) per A allele and a positive age by genotype interaction such that BMI increased faster with age (p = 10(-23)). We also fitted a linear mixed effects model to relate genotype to the BMI curve inflection points adiposity peak (AP) in infancy and AR. Carriage of two minor alleles at rs9939609 was associated with lower BMI at AP (-0.40% (95% CI: -0.74, -0.06), p = 0.02), higher BMI at AR (0.93% (95% CI: 0.22, 1.64), p = 0.01), and earlier AR (-4.72% (-5.81, -3.63), p = 10(-17)), supporting cross-sectional results. Overall, we confirm the expected association between variation at rs9939609 and BMI in childhood, but only after an inverse association between the same variant and BMI in infancy. Patterns are consistent with a shift on the developmental scale, which is reflected in association with the timing of AR rather than just a global increase in BMI. Results provide important information about longitudinal gene effects and about the role of FTO in adiposity. The associated shifts in developmental timing have clinical importance with respect to known relationships between AR and both later-life BMI and metabolic disease risk.

Childhood socioeconomic position and objectively measured physical capability levels in adulthood: a systematic review and meta-analysis

BACKGROUND

Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood.

METHODS AND FINDINGS

Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained from study investigators. Results were provided by all study investigators in a standard format and pooled using random-effects meta-analyses. 19 studies were included in the review. Total sample sizes in meta-analyses ranged from N = 17,215 for chair rise time to N = 1,061,855 for grip strength. Although heterogeneity was detected, there was consistent evidence in age adjusted models that lower childhood SEP was associated with modest reductions in physical capability levels in adulthood: comparing the lowest with the highest childhood SEP there was a reduction in grip strength of 0.13 standard deviations (95% CI: 0.06, 0.21), a reduction in mean walking speed of 0.07 m/s (0.05, 0.10), an increase in mean chair rise time of 6% (4%, 8%) and an odds ratio of an inability to balance for 5s of 1.26 (1.02, 1.55). Adjustment for the potential mediating factors, adult SEP and body size attenuated associations greatly. However, despite this attenuation, for walking speed and chair rise time, there was still evidence of moderate associations.

CONCLUSIONS

Policies targeting socioeconomic inequalities in childhood may have additional benefits in promoting the maintenance of independence in later life.

The motor phenotype of Parkinson's disease in relation to age at onset

BACKGROUND

Parkinson's disease (PD) is heterogeneous and age at onset may define variation in clinical phenotype. Most previous studies have used various age cut-offs and have been based on clinical case series.

METHODS

We have studied the association between clinical features and age of onset in 358 community-based and regional patients with PD.

RESULTS

Tremor at presentation is twice as common in those with onset over 64 years as compared to those with onset under 45 (early onset PD - EOPD) and becomes more common with increasing age at onset (p values for trend ≤ 0.004). Dystonia affects 60% of those with EOPD, shows a curvilinear relationship with age at onset (cubic versus linear p=0.01) with highest risk in patients whose disease began before 48 years. In this study age at onset was a strong predictor of the development of dyskinesias, with younger age associated with a higher risk of dyskinesias. Following multivariable analysis, allowing for possibly confounding factors (disease duration, L-DOPA dosage, L-DOPA treatment duration) younger age at onset, (less than 55 years) predicted the development of L-DOPA induced dyskinesia (odds ratio <45 years 2.1, 95% CI 1.0, 4.8; odds ratio < 55 years 3.8, 95% CI 1.8, 8.0). Only 2/70 (2.9%) EOPD patients carried pathogenic parkin or PINK1 mutations and the clinical differences between early and late onset disease were not explained by the presence of mutations in these genes.

DISCUSSION

This study highlights the clinical differences between early and late onset PD, which have important implications for diagnosis and management.

Associations of FTO and MC4R Variants with Obesity Traits in Indians and the Role of Rural/Urban Environment as a Possible Effect Modifier

Few studies have investigated the association between genetic variation and obesity traits in Indian populations or the role of environmental factors as modifiers of these relationships. In the context of rapid urbanisation, resulting in significant lifestyle changes, understanding the aetiology of obesity is important. We investigated associations of FTO and MC4R variants with obesity traits in 3390 sibling pairs from four Indian cities, most of whom were discordant for current dwelling (rural or urban). The FTO variant rs9939609 predicted increased weight (0.09 Z-scores, 95% CI: 0.03, 0.15) and BMI (0.08 Z-scores, 95% CI: 0.02, 0.14). The MC4R variant rs17782313 was weakly associated with weight and hip circumference (P < .05). There was some indication that the association between FTO and weight was stronger in urban than that in rural dwellers (P for interaction = .03), but no evidence for effect modification by diet or physical activity. Further studies are needed to investigate ways in which urban environment may modify genetic risk of obesity.

Sociodemographic patterning of non-communicable disease risk factors in rural India: a cross sectional study

OBJECTIVES

To investigate the sociodemographic patterning of non-communicable disease risk factors in rural India.

DESIGN

Cross sectional study.

SETTING

About 1600 villages from 18 states in India. Most were from four large states due to a convenience sampling strategy.

PARTICIPANTS

1983 (31% women) people aged 20-69 years (49% response rate).

MAIN OUTCOME MEASURES

Prevalence of tobacco use, alcohol use, low fruit and vegetable intake, low physical activity, obesity, central adiposity, hypertension, dyslipidaemia, diabetes, and underweight.

RESULTS

Prevalence of most risk factors increased with age. Tobacco and alcohol use, low intake of fruit and vegetables, and underweight were more common in lower socioeconomic positions; whereas obesity, dyslipidaemia, and diabetes (men only) and hypertension (women only) were more prevalent in higher socioeconomic positions. For example, 37% (95% CI 30% to 44%) of men smoked tobacco in the lowest socioeconomic group compared with 15% (12% to 17%) in the highest, while 35% (30% to 40%) of women in the highest socioeconomic group were obese compared with 13% (7% to 19%) in the lowest. The age standardised prevalence of some risk factors was: tobacco use (40% (37% to 42%) men, 4% (3% to 6%) women); low fruit and vegetable intake (69% (66% to 71%) men, 75% (71% to 78%) women); obesity (19% (17% to 21%) men, 28% (24% to 31%) women); dyslipidaemia (33% (31% to 36%) men, 35% (31% to 38%) women); hypertension (20% (18% to 22%) men, 22% (19% to 25%) women); diabetes (6% (5% to 7%) men, 5% (4% to 7%) women); and underweight (21% (19% to 23%) men, 18% (15% to 21%) women). Risk factors were generally more prevalent in south Indians compared with north Indians. For example, the prevalence of dyslipidaemia was 21% (17% to 33%) in north Indian men compared with 33% (29% to 38%) in south Indian men, while the prevalence of obesity was 13% (9% to 17%) in north Indian women compared with 24% (19% to 30%) in south Indian women.

CONCLUSIONS

The prevalence of most risk factors was generally high across a range of sociodemographic groups in this sample of rural villagers in India; in particular, the prevalence of tobacco use in men and obesity in women was striking. However, given the limitations of the study (convenience sampling design and low response rate), cautious interpretation of the results is warranted. These data highlight the need for careful monitoring and control of non-communicable disease risk factors in rural areas of India.

Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

Equity in access to total joint replacement of the hip and knee in England: cross sectional study

OBJECTIVE

To explore geographical and sociodemographic factors associated with variation in equity in access to total hip and knee replacement surgery.

DESIGN

Combining small area estimates of need and provision to explore equity in access to care.

SETTING

English census wards.

SUBJECTS

Patients throughout England who needed total hip or knee replacement and numbers who received surgery.

MAIN OUTCOME MEASURES

Predicted rates of need (derived from the Somerset and Avon Survey of Health and English Longitudinal Study of Ageing) and provision (derived from the hospital episode statistics database). Equity rate ratios comparing rates of provision relative to need by sociodemographic, hospital, and distance variables.

RESULTS

For both operations there was an "n" shaped curve by age. Compared with people aged 50-59, those aged 60-84 got more provision relative to need, while those aged >or=85 received less total hip replacement (adjusted rate ratio 0.68, 95% confidence interval 0.65 to 0.72) and less total knee replacement (0.87, 0.82 to 0.93). Compared with women, men received more provision relative to need for total hip replacement (1.08, 1.05 to 1.10) and total knee replacement (1.31, 1.28 to 1.34). Compared with the least deprived, residents in the most deprived areas got less provision relative to need for total hip replacement (0.31, 0.30 to 0.33) and total knee replacement (0.33, 0.31 to 0.34). For total knee replacement, those in urban areas got higher provision relative to need, but for total hip replacement it was highest in villages/isolated areas. For total knee replacement, patients living in non-white areas received more provision relative to need (1.04, 1.00 to 1.07) than those in predominantly white areas, but for total hip replacement there was no effect. Adjustment for hospital characteristics did not attenuate the effects.

CONCLUSIONS

There is evidence of inequity in access to total hip and total knee replacement surgery by age, sex, deprivation, rurality, and ethnicity. Adjustment for hospital and distance did not attenuate these effects. Policy makers should examine factors at the level of patients or primary care to understand the determinants of inequitable provision.

SITAR--a useful instrument for growth curve analysis

Background Growth curve analysis is a statistical issue in life course epidemiology. Height in puberty involves a growth spurt, the timing and intensity of which varies between individuals. Such data can be summarized with individual Preece–Baines (PB) curves, and their five parameters then related to earlier exposures or later outcomes. But it involves fitting many curves.

Methods We present an alternative SuperImposition by Translation And Rotation (SITAR) model, a shape invariant model with a single fitted curve. Curves for individuals are matched to the mean curve by shifting their curve up–down (representing differences in mean size) and left–right (for differences in growth tempo), and the age scale is also shrunk or stretched to indicate how fast time passes in the individual (i.e. velocity). These three parameters per individual are estimated as random effects while fitting the curve. The outcome is a mean curve plus triplets of parameters per individual (size, tempo and velocity) that summarize the individual growth patterns. The data are heights for Christ’s Hospital School (CHS) boys aged 9–19 years (N = 3245, n = 129 508), and girls with Turner syndrome (TS) aged 9–18 years from the UK Turner Study (N = 105, n = 1321).

Results The SITAR model explained 99% of the variance in both datasets [residual standard deviation (RSD) 6–7 mm], matching the fit of individually-fitted PB curves. In CHS, growth tempo was associated with insulin-like growth factor-1 measured 50 years later (P = 0.01, N = 1009). For the girls with TS randomized to receive oxandrolone from 9 years, velocity was substantially increased compared with placebo (P = 10⁻⁸).

Conclusions The SITAR growth curve model is a useful epidemiological instrument for the analysis of height in puberty.

Socio-economic disadvantage from childhood to adulthood and locomotor function in old age: a lifecourse analysis of the Boyd Orr and Caerphilly prospective studies

BACKGROUND

Socio-economic influences over a lifetime impact on health and may contribute to poor physical functioning in old age.

METHODS

The authors examined the impact of both childhood and adulthood socio-economic factors on locomotor function at 63-86 years (measured with the get up and go timed walk and flamingo balance test) in the UK-based Boyd Orr (n=405) and Caerphilly (n=1196) prospective cohorts.

RESULTS

There was a marked reduction in walking speed and balance time with increasing age. Each year of age was associated with a 1.7% slower walk time and a 14% increased odds of poor balance. Participants who moved from a low socio-economic position in childhood to a high socio-economic position in adulthood had 3% slower walking times (95% CI -2% to 8%) than people with a high socio-economic position in both periods. Participants who moved from a high socio-economic position in childhood to a low adulthood socio-economic position had 5% slower walking times (95% CI -2% to 12%). Participants with a low socio-economic position in both periods had 10% slower walking times (95% CI 5% to 16%; p for trend <0.001). In Boyd Orr, low socio-economic position in childhood was associated with poor balance in old age (OR per worsening category=1.26; 95% CI 1.01 to 1.57; p=0.043), as was socio-economic position in adulthood (OR=1.71; 95% CI 1.20 to 2.45; p=0.003). Similar associations were not observed in Caerphilly.

CONCLUSION

Accumulating socio-economic disadvantage from childhood to adulthood is associated with slower walking time in old age, with mixed results for balance ability.

An analysis of prospective risk factors for aortic stiffness in men: 20-year follow-up from the Caerphilly prospective study

Arterial stiffness is an important determinant of cardiovascular risk. The precise risk factors for arterial stiffening remain unclear. We aimed to identify potential risk factors using prospective exposure data from the Caerphilly Prospective Study. Aortic pulse wave velocity and augmentation index were measured in 825 men and related to current (2004) and baseline (1979-1988) anthropometric, hemodynamic, and biochemical factors. The mean age of the men was 74 years, with an average follow-up of 20 years. The only independent baseline predictors of current velocity were pulse pressure (standardized beta-coefficient: 0.58), C-reactive protein (0.35), glucose (0.25), and waist circumference (0.23). The sole baseline predictor of current augmentation index was fibrinogen (0.78). After additional adjustment for the corresponding current risk factor, pulse wave velocity was best related to cumulative exposure to C-reactive protein, whereas augmentation index was most strongly related to current levels. Velocity was also more strongly correlated with baseline levels of triglycerides and smoking but with current waist circumference. The pulse pressure heart rate product assessed over the whole of 20 years was independently correlated with aortic pulse wave velocity but not augmentation index. Other than blood pressure, established cardiovascular risk factors have only a modest effect on aortic stiffness and wave reflection. Inflammation and the level of repetitive cyclic stress are important predictors of aortic stiffness, whereas wave reflection is predicted by acute inflammation only. Adequate control of pulse pressure and heart rate, as well as reducing inflammation, may, in the long-term, retard aortic stiffening, although this remains to be tested directly.

The effect of rural-to-urban migration on obesity and diabetes in India: a cross-sectional study

BACKGROUND

Migration from rural areas of India contributes to urbanisation and may increase the risk of obesity and diabetes. We tested the hypotheses that rural-to-urban migrants have a higher prevalence of obesity and diabetes than rural nonmigrants, that migrants would have an intermediate prevalence of obesity and diabetes compared with life-long urban and rural dwellers, and that longer time since migration would be associated with a higher prevalence of obesity and of diabetes.

METHODS AND FINDINGS

The place of origin of people working in factories in north, central, and south India was identified. Migrants of rural origin, their rural dwelling sibs, and those of urban origin together with their urban dwelling sibs were assessed by interview, examination, and fasting blood samples. Obesity, diabetes, and other cardiovascular risk factors were compared. A total of 6,510 participants (42% women) were recruited. Among urban, migrant, and rural men the age- and factory-adjusted percentages classified as obese (body mass index [BMI] >25 kg/m(2)) were 41.9% (95% confidence interval [CI] 39.1-44.7), 37.8% (95% CI 35.0-40.6), and 19.0% (95% CI 17.0-21.0), respectively, and as diabetic were 13.5% (95% CI 11.6-15.4), 14.3% (95% CI 12.2-16.4), and 6.2% (95% CI 5.0-7.4), respectively. Findings for women showed similar patterns. Rural men had lower blood pressure, lipids, and fasting blood glucose than urban and migrant men, whereas no differences were seen in women. Among migrant men, but not women, there was weak evidence for a lower prevalence of both diabetes and obesity among more recent (

CONCLUSIONS

Migration into urban areas is associated with increases in obesity, which drive other risk factor changes. Migrants have adopted modes of life that put them at similar risk to the urban population. Gender differences in some risk factors by place of origin are unexpected and require further exploration. Please see later in the article for the Editors' Summary.

Collapse

Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Aged
• Cross-Sectional Studies
• Diabetes Mellitus/epidemiology
• Female
• Humans
• India/epidemiology
• Male
• Middle Aged
• Obesity/epidemiology
• Population Dynamics
• Risk Factors
• Socioeconomic Factors
• Young Adult

Collapse

Grants

• Wellcome Trust
• 084674 Wellcome Trust
• G0600705 Medical Research Council
• GR070797MF Wellcome Trust

Collapse

Systematic review: accuracy of anti-citrullinated Peptide antibodies for diagnosing rheumatoid arthritis

BACKGROUND

Early recognition and treatment of rheumatoid arthritis is important to prevent irreversible joint damage. Anti-citrullinated peptide antibodies (ACPA) have been suggested for early diagnosis.

PURPOSE

To compare the accuracy of ACPA and rheumatoid factor in diagnosing rheumatoid arthritis in patients with early symptoms of the disease.

DATA SOURCES

10 medical databases from inception to September 2009, with no language or publication restrictions, and references of included studies.

STUDY SELECTION

Two independent reviewers screened searches. Full articles were assessed by one reviewer and checked by a second reviewer to identify studies that reported 2 x 2 data on ACPA for the diagnosis of rheumatoid arthritis (by 1987 American College of Rheumatology criteria).

DATA EXTRACTION

One reviewer abstracted data on patient characteristics, ACPA details, and 2 x 2 data and assessed study quality by using the QUADAS tool. A second reviewer checked extractions.

DATA SYNTHESIS

151 studies were included, with considerable heterogeneity in sensitivity (range, 12% to 93%) and specificity (range, 63% to 100%). In cohort studies that investigated second-generation anti-cyclic citrullinated peptide antibodies (anti-CCP2) in patients with early rheumatoid arthritis (<2 years), summary sensitivity and specificity were 57% (95% CI, 51% to 63%) and 96% (CI, 93% to 97%), respectively. Case-control and cross-sectional studies and studies of patients with established rheumatoid arthritis all overestimated sensitivity. Anti-CCP2 had greater specificity than rheumatoid factor (96% vs. 86%), with similar sensitivity. Evidence was insufficient to ascertain whether the combination of anti-CCP2 and rheumatoid factor provides additional benefit over anti-CCP2 alone.

LIMITATIONS

Most studies used a diagnostic case-control design, which overestimated sensitivity. Items relating to study quality were rarely reported. Publication bias could not be assessed.

CONCLUSION

Anti-CCP2 should be included in the work-up of patients with early symptoms of rheumatoid arthritis.

UK Renal Registry 12th Annual Report (December 2009): chapter 13: the UK Renal Registry advanced CKD study: frequency of incorrect reporting of date of start of RRT

BACKGROUND

A preliminary review of the UK Renal Registry (UKRR) pre-RRT study data revealed results suggesting that, for some patients, the date of start of renal replacement therapy (RRT), as reported to the UKRR, was incorrect and often significantly later than the true date of start. A more detailed study then aimed to validate a set of criteria to identify patients with an incorrect start date.

METHODS

Pre-RRT laboratory data were electronically extracted from 8,810 incident RRT patients from 9 UK renal centres. Any patient with a low urea (<15 mmol/L) at the start of RRT or with a substantial improvement in kidney function (either a fall in urea >10 mmol/L or rise in eGFR >2 ml/ min/1.73 m) within the two months prior to RRT were considered to potentially have an incorrect date of start. In 4 selected centres, the electronic patient records of all patients flagged were reviewed to validate these criteria.

RESULTS

Of 8,810 patients, 1,616 (18.3%) were flagged by the identification criteria as having a potentially incorrect date of start of RRT, although a single centre accounted for 41% of the total flagged cohort. Of these flagged patients, 61.7% had been assigned an incorrect date of start of haemodialysis (HD), 5.7% had evidence of acute RRT being given before the reported date of start of HD and 9.2% had evidence of starting peritoneal dialysis exchanges prior to the reported date of start. Of those flagged, 10.7% had a correct date of start of RRT.

CONCLUSIONS

Accurate reporting of RRT episodes is vital for the analysis of time dependent studies such as survival or time to transplantation. A proportion of patients starting RRT were assigned an incorrect start date. In order to improve the accuracy of this reporting the UK Renal Registry must work with renal centres and clinical staff on improving data input for the start of RRT.

Comparison of the associations of body mass index and measures of central adiposity and fat mass with coronary heart disease, diabetes, and all-cause mortality: a study using data from 4 UK cohorts

BACKGROUND

Measures of regional adiposity have been proposed as alternatives to the measurement of body mass index (BMI) for identifying persons at risk of future disease.

OBJECTIVE

The objective was to compare the magnitudes of association of BMI and alternative measurements of adiposity with coronary heart disease, diabetes, and cardiovascular disease risk factors and all-cause mortality.

DESIGN

Data from 4 cohorts of adults [3937 women from the British Women's Heart and Health Study (BWHHS); 2367 and 1950 men from phases 1 and 3, respectively, of the Caerphilly Prospective Study (CaPS); 403 men and women from the Boyd Orr Study; and 789 men and women from the Maidstone-Dewsbury Study] were analyzed.

RESULTS

The magnitudes of associations of BMI with incident coronary heart disease and cardiovascular disease risk factors were similar to those with measurements of central adiposity [waist circumference (WC), waist-hip ratio (WHR), or waist-height ratio (WHtR)] and more direct measurements of fat mass (bioimpedance/skinfold thickness). In CaPS (men only), there was no strong evidence of differences in the strengths of association with incident diabetes between BMI, WC, WHR, and WHtR (P for heterogeneity > 0.49 for all). In the BWHHS (women only), there was statistical evidence that WC [hazard ratio (HR): 2.35; 95% CI: 2.03, 2.73] and WHtR (HR: 2.29; 95% CI: 1.98, 2.66) were more strongly associated with diabetes than with BMI (HR: 1.80; 95% CI: 1.59, 2.04) (P for heterogeneity < 0.02 for both). Central adiposity measurements were positively associated with all-cause mortality, as was BMI, but only when those with a BMI (in kg/m(2)) <22.5 were removed from the analyses.

CONCLUSION

No strong evidence supports replacing BMI in clinical or public health practice with other adiposity measures.

Validity of patient-derived disability and clinical data in multiple sclerosis

Patient-derived historical data are widely employed to make fundamental management decisions in multiple sclerosis, although the validity of the information provided is unclear. The objectives of this study were to determine validity of patient-derived historical data and to describe the utility of a locally relevant, patient-administered questionnaire designed to ascertain current disability and other important disease milestones. A well-described cohort of 99 patients was identified for whom comparable, detailed, prospective longitudinal clinician-derived data were available. Patient-derived data were collected by completion of a standardized questionnaire or telephone interview for comparison. Reliability analysis for current Expanded Disability Status Scale (EDSS) demonstrated an intraclass correlation coefficient of 0.79 between questionnaire and clinician-derived data in 79 patients, with complete agreement in 75.9%. Intraclass correlation coefficient for year of disease onset, diagnosis and onset of secondary progression was 0.86, 0.91 and 0.78, respectively. Time to EDSS >4.0, 6.0 and 8.0 all had an intraclass correlation coefficient of >0.9. Less robust agreement was observed for current disease course (Kappa coefficient 0.71), initial relapse rate (intraclass correlation coefficient 0.37) and clinical features at disease onset (Kappa 0.25). We conclude that self-reported questionnaires can provide reliable current and retrospective data on time-to-disability milestones with high levels of correlation observed for some additional elements, supporting the use of selected components of patient-derived data in clinical practice and for epidemiological studies.

New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes.

Is sticky blood bad for the brain?: Hemostatic and inflammatory systems and dementia in the Caerphilly Prospective Study

OBJECTIVE

Hemostasis and inflammation have been implicated in dementia. This study investigates the role of specific hemostatic and inflammatory pathways with incident vascular and nonvascular dementia.

METHODS AND RESULTS

This was a prospective study of a population sample of men aged 65 to 84 years, with baseline assessment of hemostatic and inflammatory factors and cognition measured 17 years later. The sample included 865 men (59 had dementia and 112 had cognitive impairment, not dementia), free of vascular disease at baseline and for whom hemostatic and inflammatory marker data were available and cognitive status was known. A total of 15 hemostatic and 6 inflammatory markers were assessed. Factor analysis was used to identify hemostatic subsystems. The National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurologie criteria were used to identify vascular dementia. By using standardized (z) scores for hemostatic and inflammatory markers, and after adjustment for age and risk factors, vascular dementia was associated with fibrinogen (hazard ratio [HR], 1.68; 95% confidence interval [CI], 1.02-2.76), factor VIII (HR, 1.79; 95% CI, 1.09-3.00), and plasminogen activator inhibitor 1 (HR, 3.13; 95% CI, 1.73-5.70). For vascular dementia, the HR risk from high levels of all three hemostatic variables (fibrinogen, factor VIII, and plasminogen activator inhibitor 1) was 2.97 (P<0.001). Inflammatory factors were not associated with vascular dementia.

CONCLUSIONS

The associations of these hemostatic markers with vascular dementia may implicate clot formation as the primary mechanism and are consistent with a microinfarct model of vascular dementia.

Multiple sclerosis risk sharing scheme: two year results of clinical cohort study with historical comparator

OBJECTIVE

To generate evidence on the longer term cost effectiveness of disease modifying treatments in patients with relapsing-remitting multiple sclerosis.

DESIGN

Prospective cohort study with historical comparator.

SETTING

Specialist multiple sclerosis clinics in 70 centres in the United Kingdom.

PARTICIPANTS

Patients with relapsing-remitting multiple sclerosis who started treatment from May 2002 to April 2005 under the UK risk sharing scheme.

INTERVENTIONS

Treatment with interferon beta or glatiramer acetate in accordance with guidelines of the UK Association of British Neurologists.

MAIN OUTCOME MEASURES

Observed utility weighted progression in disability at two years' follow-up assessed on the expanded disability status scale (EDSS) compared with that expected by applying the progression rates in a comparator dataset, modified for patients receiving treatment by multiplying by the hazard ratio derived separately for each disease modifying treatment from the randomised trials.

RESULTS

In the primary per protocol analysis, progression in disability was worse than that predicted and worse than that in the untreated comparator dataset ("deviation score" of 113%; excess in mean disability status scale 0.28). In sensitivity analyses, however, the deviation score varied from -72% (using raw baseline disability status scale scores, rather than applying a "no improvement" algorithm) to 156% (imputing missing data for year two from progression rates for year one).

CONCLUSIONS

It is too early to reach any conclusion about the cost effectiveness of disease modifying treatments from this first interim analysis. Important methodological issues, including the need for additional comparator datasets, the potential bias from missing data, and the impact of the "no improvement" rule, will need to be addressed and long term follow-up of all patients is essential to secure meaningful results. Future analyses of the cohort are likely to be more informative, not least because they will be less sensitive to short term fluctuations in disability.

Clinical presentation and initial management of black men and white men with prostate cancer in the United Kingdom: the PROCESS cohort study

Background:

In the United States, Black men have a higher risk of prostate cancer and worse survival than do White men, but it is unclear whether this is because of differences in diagnosis and management. We re-examined these differences in the United Kingdom, where health care is free and unlikely to vary by socioeconomic status.

Methods:

This study is a population-based retrospective cohort study of men diagnosed with prostate cancer with data on ethnicity, prognostic factors, and clinical care. A Delphi panel considered the appropriateness of investigations and treatments received.

Results:

At diagnosis, Black men had similar clinical stage and Gleason scores but higher age-adjusted prostate-specific antigen levels (geometric mean ratio 1.41, 95% confidence interval (95% CI): 1.15–1.73). Black men underwent more investigations and were more likely to undergo radical treatment, although this was largely explained by their younger age. Even after age adjustment, Black men were more likely to undergo a bone scan (odds ratio 1.37, 95% CI: 1.05–1.80). The Delphi analysis did not suggest differential management by ethnicity.

Conclusions:

This UK-based study comparing Black men with White men found no evidence of differences in disease characteristics at the time of prostate cancer diagnosis, nor of under-investigation or under-treatment in Black men.