Statins increase the risk of new-onset type 2 diabetes mellitus. We aimed to assess whether this increase in risk is a consequence of inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the intended drug target.
We used single nucleotide polymorphisms in the HMGCR gene, rs17238484 (for the main analysis) and rs12916 (for a subsidiary analysis) as proxies for HMGCR inhibition by statins. We examined associations of these variants with plasma lipid, glucose, and insulin concentrations; bodyweight; waist circumference; and prevalent and incident type 2 diabetes. Study-specific effect estimates per copy of each LDL-lowering allele were pooled by meta-analysis. These findings were compared with a meta-analysis of new-onset type 2 diabetes and bodyweight change data from randomised trials of statin drugs. The effects of statins in each randomised trial were assessed using meta-analysis.
Data were available for up to 223 463 individuals from 43 genetic studies. Each additional rs17238484-G allele was associated with a mean 0·06 mmol/L (95% CI 0·05–0·07) lower LDL cholesterol and higher body weight (0·30 kg, 0·18–0·43), waist circumference (0·32 cm, 0·16–0·47), plasma insulin concentration (1·62%, 0·53–2·72), and plasma glucose concentration (0·23%, 0·02–0·44). The rs12916 SNP had similar effects on LDL cholesterol, bodyweight, and waist circumference. The rs17238484-G allele seemed to be associated with higher risk of type 2 diabetes (odds ratio [OR] per allele 1·02, 95% CI 1·00–1·05); the rs12916-T allele association was consistent (1·06, 1·03–1·09). In 129 170 individuals in randomised trials, statins lowered LDL cholesterol by 0·92 mmol/L (95% CI 0·18–1·67) at 1-year of follow-up, increased bodyweight by 0·24 kg (95% CI 0·10–0·38 in all trials; 0·33 kg, 95% CI 0·24–0·42 in placebo or standard care controlled trials and −0·15 kg, 95% CI −0·39 to 0·08 in intensive-dose vs moderate-dose trials) at a mean of 4·2 years (range 1·9–6·7) of follow-up, and increased the odds of new-onset type 2 diabetes (OR 1·12, 95% CI 1·06–1·18 in all trials; 1·11, 95% CI 1·03–1·20 in placebo or standard care controlled trials and 1·12, 95% CI 1·04–1·22 in intensive-dose vs moderate dose trials).
The increased risk of type 2 diabetes noted with statins is at least partially explained by HMGCR inhibition.
The funding sources are cited at the end of the paper.
Social disadvantage across the life course is associated with a greater risk of coronary heart disease (CHD) and with established CHD risk factors, but less is known about whether novel CHD risk factors show the same patterns. The Medical Research Council National Survey of Health and Development was used to investigate associations between occupational socioeconomic position during childhood, early adulthood and middle age and markers of inflammation (C-reactive protein, interleukin-6), endothelial function (E-selectin, tissue-plasminogen activator), adipocyte function (leptin, adiponectin) and pancreatic beta cell function (proinsulin) measured at 60–64 years. Life course models representing sensitive periods, accumulation of risk and social mobility were compared with a saturated model to ascertain the nature of the relationship between social class across the life course and each of these novel CHD risk factors. For interleukin-6 and leptin, low childhood socioeconomic position alone was associated with high risk factor levels at 60–64 years, while for C-reactive protein and proinsulin, cumulative effects of low socioeconomic position in both childhood and early adulthood were associated with higher (adverse) risk factor levels at 60–64 years. No associations were observed between socioeconomic position at any life period with either endothelial marker or adiponectin. Associations for C-reactive protein, interleukin-6, leptin and proinsulin were reduced considerably by adjustment for body mass index and, to a lesser extent, cigarette smoking. In conclusion, socioeconomic position in early life is an important determinant of several novel CHD risk factors. Body mass index may be an important mediator of these relationships.
•We examine associations of life course socioeconomic position (SEP) with novel coronary heart disease risk markers using novel methods to compare different life course models.•SEP during childhood was important for IL-6 and leptin, while SEP during both childhood and early adulthood was important for CRP and proinsulin.•BMI (but not smoking) explained a large part of these relationships.
Socioeconomic position; Life course; Inflammation; Endothelial; Adipocyte; Proinsulin; Birth cohort
Participation in leisure-time physical activity benefits health and is thought to be more prevalent in higher socioeconomic groups. Evidence indicates that childhood socioeconomic circumstances may have long-term influences on adult health and behaviour; however, it is unclear if this extends to an influence on adult physical activity. The aim of this review is to examine whether a lower childhood socioeconomic position is associated with lower levels of leisure-time physical activity during adulthood.
Keywords will be used to systematically search five online databases and additional studies will be located through a search of reference lists. At least two researchers working independently will screen search results assess the quality of included studies and extract all relevant data. Studies will be included if they are English language publications that test the association between at least one indicator of childhood socioeconomic position and a leisure-time physical activity outcome measured during adulthood. Any disagreements and discrepancies arising during the conduct of the study will be resolved through discussion.
This study will address the gap in evidence by systematically reviewing the published literature to establish whether childhood socioeconomic position is related to adult participation in leisure-time physical activity. The findings may be used to inform future research and policy.
Systematic review registration
Electronic supplementary material
The online version of this article (doi:10.1186/2046-4053-3-141) contains supplementary material, which is available to authorized users.
Socioeconomic inequalities; Occupation; Education; Socioeconomic position; Physical activity; Exercise; Life course
Antecedent blood pressure (BP) may contribute to cardiovascular disease (CVD) independent of current BP. Blood pressure is associated with left ventricular mass index (LVMI) which independently predicts CVD. We investigated the relationship between midlife BP from age 36 to 64 and LVMI at 60–64 years.
Methods and results
A total of 1653 participants in the British 1946 Birth Cohort underwent BP measurement and echocardiography aged 60–64. Blood pressure had previously been measured at 36, 43, and 53 years. We investigated associations between BP at each age and rate of change in systolic blood pressure (SBP) between 36–43, 43–53, and 53–60/64 years on LVMI at 60–64 years. Blood pressure from 36 years was positively associated with LVMI. Association with SBP at 53 years was independent of SBP at 60–64 years and other potential confounders (fully adjusted β at 53 years = 0.19 g/m2; 95% CI: 0.11, 0.27; P < 0.001). Faster rates of increase in SBP from 43 to 53 years and 53 to 60/64 years were associated with increased LVMI. Similar relationships were seen for diastolic, pulse, and mean pressure. Rate of increase in SBP between 43–53 years was associated with largest change in LVMI (β at 43–53 years = 3.12 g/m2; 95% CI: 1.53, 4.72; P < 0.001). People on antihypertensive medication (43 years onwards) had greater LVMI even after adjustment for current BP (β at 43 years = 12.36 g/m2; 95% CI: 3.19, 21.53; P = 0.008).
Higher BP in midlife and rapid rise of SBP in 5th decade is associated with higher LVMI in later life, independent of current BP. People with treated hypertension have higher LVMI than untreated individuals, even accounting for their higher BP. Our findings emphasize importance of midlife BP as risk factor for future CVD.
Blood pressure; Left ventricular mass; Left ventricular hypertrophy; Echocardiography
Atherosclerosis begins early in life and obesity is a key determinant. We investigated the role of BMI and height from infancy to adulthood in presenting with high adulthood carotid intima-media thickness (cIMT).
Approach and Results
Odds ratios (OR) of BMI and height Z-scores at 2, 4, 6, 7, 11, 15, 20 years, and changes between 2-4, 4-7, 7-15, 15-20 years, for cIMT at 60-64 years in the upper quartile were estimated for 604 males and 669 females. Confounding by early life environments, mediating by body size and cardio-metabolic measures at 60-64 years, and effect modification were investigated. In males, there was positive association of BMI at 4 years (OR 1.256; 95% CI 1.026, 1.538) and 20 years (1.282; 1.022, 1.609), negative association of height at 4 years (0.780; 0.631, 0.964), and negative association of height growth between 2-4 years (0.698; 0.534, 0.913) with high cIMT. The childhood estimates were robust, but the estimate for BMI at 20 years was attenuated by adjustment for BMI at 60-64 years. The protective influence of greater early childhood height was strongest in those with the lowest systolic blood pressure at 60-64 years. In females, there was no pattern of association and all confidence intervals crossed one.
Early childhood in males might be a sensitive developmental period for atherosclerosis, where changes in BMI and height represent two distinct biological mechanisms. The maintenance of healthy weight in males from adolescence onward may be a useful strategy to avoid the atherosclerotic complications of adiposity tracking.
atherosclerosis; carotid intima-media thickness; childhood; body mass index; height; early life environments; longitudinal studies
Objective measures of physical capability are being used in a growing number of studies as biomarkers of healthy ageing. However, very little research has been done to assess the impact of physical capability on subsequent positive mental wellbeing, the maintenance of which is widely considered to be an essential component of healthy ageing. We aimed to test the associations of grip strength and walking, timed get up and go and chair rise speeds (assessed at ages 53 to 82 years) with positive mental wellbeing assessed using the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) five to ten years later. Data were drawn from five British cohorts participating in the HALCyon research collaboration. Data from each study were analysed separately and then combined using random-effects meta-analyses. Higher levels of physical capability were consistently associated with higher subsequent levels of wellbeing; for example, a 1SD increase in grip strength was associated with an age and sex-adjusted mean difference in WEMWBS score of 0.81 (0.25, 1.37), equivalent to 10% of a standard deviation (3 studies, N=3,096). When adjusted for body size, health status, living alone, socioeconomic position and neuroticism the associations remained albeit attenuated. The finding of these consistent modest associations across five studies, spanning early and later old age, highlights the importance of maintaining physical capability in later life and provides additional justification for using objective measures of physical capability as markers of healthy ageing.
physical capability; positive mental wellbeing; grip strength; walking speed; chair rise time
The APOE ε2/3/4 genotype has been associated with low-density lipoprotein cholesterol (LDL-C) and Alzheimer disease. However, evidence for associations with measures of cognitive performance in adults without dementia has been mixed, as it is for physical performance. Associations may also be evident in other genotypes implicated in LDL-C levels. As part of the Healthy Ageing across the Life Course (HALCyon) collaborative research programme, genotypic information was obtained for APOE ε2/3/4, rs515135 (APOB), rs2228671 (LDLR) and rs629301 (SORT1) from eight cohorts of adults aged between 44 and 90 + years. We investigated associations with four measures of cognitive (word recall, phonemic fluency, semantic fluency and search speed) and physical capability (grip strength, get up and go/walk speed, timed chair rises and ability to balance) using meta-analyses. Overall, little evidence for associations between any of the genotypes and measures of cognitive capability was observed (e.g. pooled beta for APOE ε4 effect on semantic fluency z score = −0.02; 95 % CI = −0.05 to 0.02; p value = 0.3; n = 18,796). However, there was borderline evidence within studies that negative effects of APOE ε4 on nonverbal ability measures become more apparent with age. Few genotypic associations were observed with physical capability measures. The findings from our large investigation of middle-aged to older adults in the general population suggest that effects of APOE on cognitive capability are at most modest and are domain- and age-specific, while APOE has little influence on physical capability. In addition, other LDL-C-related genotypes have little impact on these traits.
Electronic supplementary material
The online version of this article (doi:10.1007/s11357-014-9673-9) contains supplementary material, which is available to authorized users.
Ageing; Apolipoprotein E; Cognition; Single nucleotide polymorphism
BRCA1 mutation carriers have an 85% risk of developing breast cancer but the risk of developing non-hereditary breast cancer is difficult to assess. Our objective is to test whether a DNA methylation (DNAme) signature derived from BRCA1 mutation carriers is able to predict non-hereditary breast cancer.
In a case/control setting (72 BRCA1 mutation carriers and 72 BRCA1/2 wild type controls) blood cell DNA samples were profiled on the Illumina 27 k methylation array. Using the Elastic Net classification algorithm, a BRCA1-mutation DNAme signature was derived and tested in two cohorts: (1) The NSHD (19 breast cancers developed within 12 years after sample donation and 77 controls) and (2) the UKCTOCS trial (119 oestrogen receptor positive breast cancers developed within 5 years after sample donation and 122 controls).
We found that our blood-based BRCA1-mutation DNAme signature applied to blood cell DNA from women in the NSHD resulted in a receiver operating characteristics (ROC) area under the curve (AUC) of 0.65 (95% CI 0.51 to 0.78, P = 0.02) which did not validate in buccal cells from the same individuals. Applying the signature in blood DNA from UKCTOCS volunteers resulted in AUC of 0.57 (95% CI 0.50 to 0.64; P = 0.03) and is independent of family history or any other known risk factors. Importantly the BRCA1-mutation DNAme signature was able to predict breast cancer mortality (AUC = 0.67; 95% CI 0.51 to 0.83; P = 0.02). We also found that the 1,074 CpGs which are hypermethylated in BRCA1 mutation carriers are significantly enriched for stem cell polycomb group target genes (P <10-20).
A DNAme signature derived from BRCA1 carriers is able to predict breast cancer risk and death years in advance of diagnosis. Future studies may need to focus on DNAme profiles in epithelial cells in order to reach the AUC thresholds required of preventative measures or early detection strategies.
Cross-sectional studies reported associations between short leucocyte telomere length (LTL) and measures of vascular and cardiac damage. However, the contribution of LTL dynamics to the age-related process of cardiovascular (CV) remodelling remains unknown. In this study, we explored whether the rate of LTL shortening can predict CV phenotypes over 10-year follow-up and the influence of established CV risk factors on this relationship.
Methods and results
All the participants from the MRC National Survey of Health and Development (NSHD) with measures of LTL and traditional CV risk factors at 53 and 60–64 years and common carotid intima-media thickness (cIMT), cardiac mass and left ventricular function at 60–64 years were included. LTL was measured by real-time polymerase chain reaction and available at both time points in 1033 individuals. While LTL at 53 years was not linked with any CV phenotype at 60–64 years, a negative association was found between LTL and cIMT at 60–64 years (β = −0.017, P = 0.015). However, the strongest association was found between rate of telomere shortening between 53 and 60–64 years and values of cIMT at 60–64 years (β = −0.020, P = 0.006). This association was not affected by adjustment for traditional CV risk factors. Cardiac measurements were not associated with cross-sectional or longitudinal measures of LTL.
These findings suggest that the rate of progression of cellular ageing in late midlife (reflected by the rate of LTL attrition) relates to vascular damage, independently from contribution of CV risk factor exposure.
Ageing; Telomeres shortening; Cardiovascular diseases; Carotid artery
Using data from a nationally representative British birth cohort we characterized the type and diversity of leisure-time physical activity that 2,188 participants (age 60–64 years) engaged in throughout the year by gender and obesity. Participants most commonly reported walking (71%), swimming (33%), floor exercises (24%) and cycling (15%). Sixty-two percent of participants reported ≥2 activities in the past year and 40% reported diversity on a regular basis. Regular engagement in different types of activity (cardio-respiratory, balance/flexibility and strength) was reported by 67%, 19% and 11% of participants, respectively. We found gender differences, as well as differences by obesity status, in the activities reported, the levels of activity diversity and activity type. Non-obese participants had greater activity diversity, and more often reported activities beneficial for cardio-respiratory health and balance/flexibility than obese participants. These findings may be used to inform the development of trials of physical activity interventions targeting older adults, and those older adults with high body mass index.
Detailed assessment of physical activity (PA) in older adults is required to comprehensively describe habitual PA-levels in this growing population segment. Current evidence of population PA-levels is predominantly based on self-report.
We examined PA and sedentary behaviour in a nationally representative sample of British people aged 60–64, using individually-calibrated combined heart-rate and movement sensing and a validated questionnaire (EPAQ2), and the socio-demographic and behavioural factors that may explain between-individual variation in PA.
Between 2006–2010, 2224 participants completed EPAQ2 capturing the past year’s activity in four domains (leisure, work, transportation and domestic life) and 1787 participants provided 2–5 days of combined-sensing data. According to objective estimates, median(IQR) physical activity energy expenditure (PAEE) was 33.5 (25.3-42.2) and 35.5 (26.6- 47.3) kJ/kg/day for women and men, respectively. Median (IQR) time spent in moderate-to-vigorous PA (MVPA; >3MET), light-intensity PA (1.5-3 MET) and sedentary (<1.5 MET) was 26.0 (12.3-48.1) min/day, 5.4 (4.2-6.7) h/day and 18.0 (16.6-19.4) h/day, respectively, in women; and 41.0 (18.8-73.0) min/day, 5.2 (4.0-6.5) h/day and 17.9 (16.3-19.4) h/day in men. PAEE and time spent in MVPA were lower and sedentary time was greater in obese individuals, those with poor health, and those with lower educational attainment (women only). Questionnaire-derived PAEE and MVPA tended to have similar patterns of variation across socio-demographic strata. In the whole sample, domestic PA had the greatest relative contribution to total questionnaire-derived PAEE (58%), whereas occupational PA was the main driver among employed participants (54%). Only 2.2% of participants achieved an average of >30 min MVPA per day combined with >60 min strength-training per week.
The use of both self-report and objective monitoring to assess PA in early old age provides important information on the domains of PA, PAEE and time spent at different intensity levels. Our findings suggest PA levels are generally low and observed patterns of variation indicate specific subgroups who might benefit from targeted interventions to increase PA.
Physical activity; Sedentary behaviour; Physical activity questionnaire; Combined sensing; Birth cohort; Old age
As more people live more of their lives obese, it is unclear what impact this will have on muscle mass, strength, and quality. We aimed to examine the associations of body mass index (BMI) from age 15 years onwards with low muscle mass, strength, and quality in early old age.
A total of 1,511 men and women from a British birth cohort study with BMI measured at 15, 20, 26, 36, 43, 53, and 60–64 years and dual-energy x-ray absorptiometry scans at 60–64 years were included. Four binary outcomes identified those in the bottom sex-specific 20% of (a) appendicular lean mass (ALM) index (kilogram per square meter), (b) ALM residuals (derived from sex-specific models in which ALM (kilogram) = β0 + β1 height [meter] + β2 fat mass [kilogram]), (c) grip strength (kilogram), (d) muscle quality (grip strength [kilogram]/arm lean mass [kilogram]). Associations of BMI with each outcome were tested.
Higher BMI from age 15 years was associated with lower odds of low ALM but higher odds of low muscle quality (per 1 SD increase in BMI at 36 years, odds ratio of low ALM residuals = 0.50 [95% CI: 0.43, 0.59], and muscle quality = 1.50 [1.29, 1.75]). Greater gains in BMI were associated with lower odds of low ALM index but higher odds of low muscle quality. BMI was not associated with grip strength.
Given increases in the global prevalence of obesity, cross-cohort comparisons of sarcopenia need to consider our findings that greater gains in BMI are associated with higher muscle mass but not with grip strength and therefore with lower muscle quality.
Sarcopenia; Obesity; Life course epidemiology; Muscle mass; Strength and quality.
To compare physical activity (PA) subcomponents from EPIC Physical Activity Questionnaire (EPAQ2) and combined heart rate and movement sensing in older adults.
Participants aged 60–64y from the MRC National Survey of Health and Development in Great Britain completed EPAQ2, which assesses self-report PA in 4 domains (leisure time, occupation, transportation and domestic life) during the past year and wore a combined sensor for 5 consecutive days. Estimates of PA energy expenditure (PAEE), sedentary behaviour, light (LPA) and moderate-to-vigorous PA (MVPA) were obtained from EPAQ2 and combined sensing and compared. Complete data were available in 1689 participants (52% women).
EPAQ2 estimates of PAEE and MVPA were higher than objective estimates and sedentary time and LPA estimates were lower [bias (95% limits of agreement) in men and women were 32.3 (−61.5 to 122.6) and 29.0 (−39.2 to 94.6) kJ/kg/day for PAEE; −4.6 (−10.6 to 1.3) and −6.0 (−10.9 to −1.0) h/day for sedentary time; −171.8 (−454.5 to 110.8) and −60.4 (−367.5 to 246.6) min/day for LPA; 91.1 (−159.5 to 341.8) and 55.4 (−117.2 to 228.0) min/day for MVPA]. There were significant positive correlations between all self-reported and objectively assessed PA subcomponents (rho = 0.12 to 0.36); the strongest were observed for MVPA (rho = 0.30 men; rho = 0.36 women) and PAEE (rho = 0.26 men; rho = 0.25 women).
EPAQ2 produces higher estimates of PAEE and MVPA and lower estimates of sedentary and LPA than objective assessment. However, both methodologies rank individuals similarly, suggesting that EPAQ2 may be used in etiological studies in this population.
Previous studies have found associations between cognitive function and chronic kidney disease. We aimed to explore possible explanations for this association in the Medical Research Council National Survey of Health and Development, a prospective birth cohort representative of the general British population.
Cognitive function at age 60–64 years was quantified using five measures (verbal memory, letter search speed and accuracy, simple and choice reaction times) and glomerular filtration rate (eGFR) at the same age was estimated using cystatin C. The cross-sectional association between cognitive function and eGFR was adjusted for background confounding factors (socioeconomic position, educational attainment), prior cognition, and potential explanations for any remaining association (smoking, diabetes, hypertension, inflammation, obesity).
Data on all the analysis variables were available for 1306–1320 study members (depending on cognitive measure). Verbal memory and simple and choice reaction times were strongly associated with eGFR. For example, the lowest quartile of verbal memory corresponded to a 4.1 (95% confidence interval 2.0, 6.2) ml/min/1.73 m2 lower eGFR relative to the highest quartile. Some of this association was explained by confounding due to socioeconomic factors, but very little of it by prior cognition. Smoking, diabetes, hypertension, inflammation and obesity explained some but not all of the remaining association.
These analyses support the notion of a shared pathophysiology of impaired cognitive and kidney function at older age, which precedes clinical disease. The implications of these findings for clinical care and research are important and under-recognised, though further confirmatory studies are required.
The relationship between weight loss and mortality has important clinical and public health significance but has proved to be complex. Evidence is mixed and particularly limited on the association between weight loss in mid-life and premature death (i.e. before 65 years of age), a small albeit important segment of total mortality. We aimed to study the association between midlife weight change and mortality accounting for health and lifestyle characteristics, and also considering potential bias due to preexisting chronic diseases and smoking status.
Longitudinal, population-based, ‘the 1946 British’ birth cohort study.
Subjects and Measures
In 2750 men and women, mortality from age 53 through 65 years was analyzed according to categories of measured 10 year weight change between 43 and 53 years. Cox's hazard ratios (HR) were progressively adjusted for socio-demographic, lifestyle and health characteristics.
Nearly 20% of participants lost weight and over 50% gained 5 kg or more in midlife. There were 164 deaths. Compared to those who gained between 2 and 5 kg, those who lost 5 kg or more had an increased risk of premature death independently of midlife physical activity, socio-economic circumstances and educational attainment. This association was unaltered when highest weight loss (lost more than 15 Kg) (p = 0.04) and early deaths were excluded (p<0.001), but was no longer significant after adjustment for cardiovascular risk factors and health status (HR = 1.8; 95% CI: 0.9 to 3.5).
The inverse association between weight loss in midlife and higher risk of premature death may be explained by vascular risk factors and ill health. In consideration of the burden of premature death, closer monitoring of weight loss in mid-life is warranted.
Background and objective: Dysregulation of respiratory mucins, MUC5AC in particular, has been implicated in respiratory disease and MUC5AC expression is up-regulated in response to environmental challenges and inflammatory mediators. The aim of this study was to examine the effect of genetic variation on susceptibility to common respiratory conditions.
Methods: The association of MUC5AC and the closely linked genes MUC2 and MUC5B with respiratory outcomes was tested in the MRC National Survey of Health and Development, a longitudinal birth cohort of men and women born in 1946. Also examined were the functional variants of the genes encoding inflammatory mediators, IL13, IL1B, IL1RN, TNFA and ERBB1, for which there is a likely influence on MUC5AC expression and were explored potential gene-gene interactions with these inflammatory mediators.
Results: Statistically significant associations between the 3'ter MUC5AC simple nucleotide polymorphism (SNP) rs1132440 and various non-independent respiratory outcomes (bronchitis, wheeze, asthma, hay fever) were reported while the adjacent loci show slight (but largely non-statistically significant) differences, presumably reflective of linkage disequilibrium (allelic association) across the region. A novel association between bronchitis and a non-synonymous functional ERBB1 SNP, rs2227983 (aka epidermal growth factor receptor:R497K, R521K) is also reported and evidence presented of interaction between MUC5AC and ERBB1 and between MUC5AC and IL1RN with respect to bronchitis. The ERBB1 result suggests a clear mechanism for a biological interaction in which the allelic variants of epidermal growth factor receptor differentially affect mucin expression.
Conclusions: The MUC5AC association and the interactions with inflammatory mediators suggest that genetically determined differences in MUC5AC expression alter susceptibility to respiratory disease.
SUMMARY AT A GLANCE
This longitudinal cohort study shows occurrence of the common respiratory conditions bronchitis, wheeze, asthma and hay fever to be associated with genetic variation in a mucin gene, MUC5AC. Functional variation in the epidermal growth factor receptor (epidermal growth factor receptor encoded by ERBB1) is also associated with bronchitis and modulates the MUC5AC effect.
airway epithelium; asthma; genetics; inflammation; respiratory function test
Substantial advances have been made in identifying common genetic variants influencing cardiometabolic traits and disease outcomes through genome wide association studies. Nevertheless, gaps in knowledge remain and new questions have arisen regarding the population relevance, mechanisms, and applications for healthcare. Using a new high-resolution custom single nucleotide polymorphism (SNP) array (Metabochip) incorporating dense coverage of genomic regions linked to cardiometabolic disease, the University College-London School-Edinburgh-Bristol (UCLEB) consortium of highly-phenotyped population-based prospective studies, aims to: (1) fine map functionally relevant SNPs; (2) precisely estimate individual absolute and population attributable risks based on individual SNPs and their combination; (3) investigate mechanisms leading to altered risk factor profiles and CVD events; and (4) use Mendelian randomisation to undertake studies of the causal role in CVD of a range of cardiovascular biomarkers to inform public health policy and help develop new preventative therapies.
In contrast to the many studies in females, there are few data in males on the relationships between childhood growth and weight gain and the timing of pubertal maturation and its relevance to adult body mass index (BMI) and body composition.
A total of 2008 males in the 1946 British Birth Cohort Study had assessment of pubertal status including voice-breaking status (no change, starting, or complete) at age 14 yr. These responses were related to growth measurements at birth (weight only) and at 2, 4, 6, 7, 11, 14, 20, 26, 36, 43, 53, and 60–64 yr. Body composition was assessed by dual-energy x-ray absorptiometry at 60–64 yr.
Males with more advanced voice-breaking status at age 14 yr had similar birth weights compared with other males; they showed faster weight gain from 0–2 yr and had higher mean weight and BMI at age 2 yr. Subsequently, they continued to accelerate in weight and BMI, and also in height, and maximum differences in body size were seen at age 14 yr. Adult height did not differ between groups, but males with advanced voice breaking had higher adult BMI and greater whole-body lean mass and greater android fat mass at 60–64 yr.
Similar to females with earlier menarche, the trajectory to earlier sexual maturation in males is manifested by faster early postnatal growth and weight gain and leads to higher adult BMI. Timing of pubertal maturation has potential relevance to adult disease risks in males. We also describe conditional height difference in sd score as a proxy marker of pubertal timing in males.
Few studies have examined the impact of childhood obesity on later kidney disease, and consequently, our understanding is very limited.
Longitudinal population-based cohort.
Setting & Participants
The Medical Research Council National Survey of Health and Development, a socially stratified sample of 5,362 singletons born in 1 week in March 1946 in England, Scotland, and Wales, of which 4,340 were analyzed.
Early-life overweight latent classes (never, prepubertal only, pubertal onset, or always), derived from repeated measurements of body mass index between ages 2 and 20 years.
Outcomes & Measurements
The primary outcome was chronic kidney disease (CKD), defined as creatinine- or cystatin C–based estimated glomerular filtration rate (eGFRcr and eGFRcys, respectively) <60 mL/min/1.73 m2 or urine albumin-creatinine ratio (UACR) ≥3.5 mg/mmol measured at age 60-64 years. Associations were explored through regression analysis, with adjustment for socioeconomic position, smoking, physical activity level, diabetes, hypertension, and overweight at ages 36 and 53 years.
2.3% of study participants had eGFRcr <60 mL/min/1.73 m2, 1.7% had eGFRcys <60 mL/min/1.73 m2, and 2.9% had UACR ≥3.5 mg/mmol. Relative to being in the never-overweight latent class, being in the pubertal-onset– or always-overweight latent classes was associated with eGFRcys-defined CKD (OR, 2.04; 95% CI, 1.09-3.82). Associations with CKD defined by eGFRcr (OR, 1.27; 95% CI, 0.71-2.29) and UACR (OR, 1.33; 95% CI, 0.70-2.54) were less marked, but in the same direction. Adjustment for lifestyle and health factors had little impact on effect estimates.
A low prevalence of CKD resulted in low statistical power. No documentation of chronicity for outcomes. All-white study population restricts generalizability.
Being overweight in early life was found to be associated with eGFRcys-defined CKD in later life. The associations with CKD defined by eGFRcr and UACR were less marked, but in the same direction. Reducing or preventing overweight in the early years of life may significantly reduce the burden of CKD in the population.
Childhood obesity; chronic kidney disease; estimated glomerular filtration rate
Telomeres are involved in cellular ageing and shorten with increasing age. If telomere length is a valuable biomarker of ageing, then telomere shortening should be associated with worse physical performance, an ageing trait, but evidence for such an association is lacking. The purpose of this study was to examine whether change in telomere length is associated with physical performance.
Using data from four UK adult cohorts (ages 53–80 years at baseline), we undertook cross-sectional and longitudinal analyses. We analysed each study separately and then used meta-analytic methods to pool the results. Physical performance was measured using walking and chair rise speed, standing balance time and grip strength. Telomere length was measured by quantitative real-time polymerase chain reaction (PCR) in whole blood at baseline and follow-up (time 1, time 2).
Total sample sizes in meta-analyses ranged from 1,217 to 3,707. There was little evidence that telomere length was associated with walking speed, balance or grip strength, though weak associations were seen with chair rise speed and grip strength at baseline (p = 0.02 and 0.01 respectively). Faster chair rise speed at follow-up, was associated with a smaller decline in telomere length between time 1 and time 2 (standardised coefficient per SD increase 0.061, 95% CI 0.006, 0.115, p = 0.03) but this was consistent with chance (p = 0.08) after further adjustment.
Whereas shortening of leukocyte telomeres might be an important measure of cellular ageing, there is little evidence that it is a strong biomarker for physical performance.
Overweight and obesity in adulthood are established risk factors for adverse cardiovascular outcomes, but the contribution of overweight in childhood to later cardiovascular risk is less clear. Evidence for a direct effect of childhood overweight would highlight early life as an important target for cardiovascular disease prevention. The aim of this study was to assess whether overweight and obesity in childhood and adolescence contribute to excess cardiovascular risk in adults.
Methods and findings
Data from three British birth cohorts, born in 1946, 1958 and 1970, were pooled for analysis (n = 11,447). Individuals were categorised, based on body mass index (BMI), as being of normal weight or overweight/obese in childhood, adolescence and adulthood. Eight patterns of overweight were defined according to weight status at these three stages. Logistic regression models were fitted to assess the associations of patterns of overweight with self-reported type 2 diabetes, hypertension, and coronary heart disease (CHD) in adulthood (34–53 years). Compared to cohort members who were never overweight, those who were obese in adulthood had increased risk of all outcomes. For type 2 diabetes, the odds ratio was higher for obese adults who were also overweight or obese in childhood and adolescence (OR 12.6; 95% CI 6.6 to 24.0) than for those who were obese in adulthood only (OR 5.5; 95% CI 3.4 to 8.8). There was no such effect of child or adolescent overweight on hypertension. For CHD, there was weak evidence of increased risk among those with overweight in childhood. The main limitations of this study concern the use of self-reported outcomes and the generalisability of findings to contemporary child populations.
Type 2 diabetes and to a lesser extent CHD risk may be affected by overweight at all stages of life, while hypertension risk is associated more strongly with weight status in adulthood.
The glucokinase regulatory protein encoded by GCKR plays an important role in glucose metabolism and a single nucleotide polymorphism (SNP) rs1260326 (P446L) in the gene has been associated with several age-related biomarkers, including triglycerides, glucose, insulin and apolipoproteins. However, associations between SNPs in the gene and other ageing phenotypes such as cognitive and physical capability have not been reported.
As part of the Healthy Ageing across the Life Course (HALCyon) collaborative research programme, men and women from five UK cohorts aged between 44 and 90+ years were genotyped for rs1260326. Meta-analysis was used to pool within-study genotypic associations between the SNP and several age-related phenotypes, including body mass index (BMI), blood lipid levels, lung function, and cognitive and physical capability.
We confirm the associations between the minor allele of the SNP and higher triglycerides and lower glucose levels. We also observed a triglyceride-independent association between the minor allele and lower BMI (pooled beta on z-score = −0.04, p-value = 0.0001, n = 16,251). Furthermore, there was some evidence for gene-environment interactions, including physical activity attenuating the effects on triglycerides. However, no associations were observed with measures of cognitive and physical capability.
Findings from middle-aged to older adults confirm associations between rs1260326 GCKR and triglycerides and glucose, suggest possible gene-environment interactions, but do not provide evidence that its relevance extends to cognitive and physical capability.
Depressive symptoms and physical performance are inversely associated, but it is unclear whether their association is bidirectional. We examined whether the association between depressive symptoms and physical performance measured using gait speed is bidirectional.
We used a national sample of 4,581 community-dwelling people aged 60 years and older from the English Longitudinal Study of Ageing (from 2002–03 to 2008-09). We fitted Generalized Estimating Equation (GEE) regression models to analyse repeated measurements of gait speed (m/sec) and elevated depressive symptoms (defined as a score of ≥4 on the eight-item Center for Epidemiological Studies-Depression scale).
Slower gait speed was associated with elevated depressive symptoms both concurrently and two years later. After adjustment for previous depressive symptoms and sociodemographic, clinical, lifestyle, psychosocial, and cognitive factors the concurrent association was partially explained (Odds Ratio [OR] 0.42, 95% confidence interval [CI], 0.30 to 0.59, per 1m/sec increase in gait speed) and the two-year lagged association fully (OR 0.75, 95% CI, 0.56 to 1.00). Elevated depressive symptoms were associated with slower gait speed. Full adjustment for covariates (including previous gait speed) partially explained both the concurrent (β regression coefficient [β] -0.038, 95% CI, -0.050 to -0.026, for participants with elevated depressive symptoms compared with those with no or one symptom) and the two-year lagged associations (β -0.017, 95% CI, -0.030 to -0.005). Subthreshold depressive symptoms (defined as a score of two or three on the eight-item Center for Epidemiological Studies-Depression scale) were also associated with slower gait speed. Full adjustment for covariates partially explained both the concurrent (β -0.029, 95% CI, -0.039 to -0.019, for participants with subthreshold symptoms compared with those with no or one symptom) and the two-year lagged associations (β -0.011, 95% CI, -0.021 to -0.001).
The inverse association between gait speed and depressive symptoms appears to be bidirectional.
Objective measures of physical capability are being used in a growing number of studies as biomarkers of healthy ageing. However, very little research has been done to assess the impact of physical capability on subsequent positive mental wellbeing, the maintenance of which is widely considered to be an essential component of healthy ageing. We aimed to test the associations of grip strength and walking, timed get up and go and chair rise speeds (assessed at ages 53 to 82 years) with positive mental wellbeing assessed using the Warwick–Edinburgh Mental Wellbeing Scale (WEMWBS) 5 to 10 years later. Data were drawn from five British cohorts participating in the Healthy Ageing across the Life Course research collaboration. Data from each study were analysed separately and then combined using random-effects meta-analyses. Higher levels of physical capability were consistently associated with higher subsequent levels of wellbeing; for example, a 1SD increase in grip strength was associated with an age and sex-adjusted mean difference in WEMWBS score of 0.81 (0.25, 1.37), equivalent to 10 % of a standard deviation (three studies, N = 3,096). When adjusted for body size, health status, living alone, socioeconomic position and neuroticism the associations remained albeit attenuated. The finding of these consistent modest associations across five studies, spanning early and later old age, highlights the importance of maintaining physical capability in later life and provides additional justification for using objective measures of physical capability as markers of healthy ageing.
Electronic supplementary material
The online version of this article (doi:10.1007/s11357-013-9553-8) contains supplementary material, which is available to authorized users.
Physical capability; Positive mental wellbeing; Grip strength; Walking speed; Chair rise time
Physical capability in later life is influenced by factors occurring across the life course, yet exposures to area conditions have only been examined cross-sectionally. Data from the National Survey of Health and Development, a longitudinal study of a 1946 British birth cohort, were used to estimate associations of area deprivation (defined as percentage of employed people working in partly skilled or unskilled occupations) at ages 4, 26, and 53 years (residential addresses linked to census data in 1950, 1972, and 1999) with 3 measures of physical capability at age 53 years: grip strength, standing balance, and chair-rise time. Cross-classified multilevel models with individuals nested within areas at the 3 ages showed that models assessing a single time point underestimate total area contributions to physical capability. For balance and chair-rise performance, associations with area deprivation in midlife were robust to adjustment for individual socioeconomic position and prior area deprivation (mean change for a 1-standard-deviation increase: balance, −7.4% (95% confidence interval (CI): −12.8, −2.8); chair rise, 2.1% (95% CI: −0.1, 4.3)). In addition, area deprivation in childhood was related to balance after adjustment for childhood socioeconomic position (−5.1%, 95% CI: −8.7, −1.6). Interventions aimed at reducing midlife disparities in physical capability should target the socioeconomic environment of individuals—for standing balance, as early as childhood.
geography; Great Britain; health status disparities; longitudinal studies; multilevel analysis; physical endurance; residence characteristics; socioeconomic factors