Background The extent to which adult height, a biomarker of the interplay of genetic endowment and early-life experiences, is related to risk of chronic diseases in adulthood is uncertain.
Methods We calculated hazard ratios (HRs) for height, assessed in increments of 6.5 cm, using individual–participant data on 174 374 deaths or major non-fatal vascular outcomes recorded among 1 085 949 people in 121 prospective studies.
Results For people born between 1900 and 1960, mean adult height increased 0.5–1 cm with each successive decade of birth. After adjustment for age, sex, smoking and year of birth, HRs per 6.5 cm greater height were 0.97 (95% confidence interval: 0.96–0.99) for death from any cause, 0.94 (0.93–0.96) for death from vascular causes, 1.04 (1.03–1.06) for death from cancer and 0.92 (0.90–0.94) for death from other causes. Height was negatively associated with death from coronary disease, stroke subtypes, heart failure, stomach and oral cancers, chronic obstructive pulmonary disease, mental disorders, liver disease and external causes. In contrast, height was positively associated with death from ruptured aortic aneurysm, pulmonary embolism, melanoma and cancers of the pancreas, endocrine and nervous systems, ovary, breast, prostate, colorectum, blood and lung. HRs per 6.5 cm greater height ranged from 1.26 (1.12–1.42) for risk of melanoma death to 0.84 (0.80–0.89) for risk of death from chronic obstructive pulmonary disease. HRs were not appreciably altered after further adjustment for adiposity, blood pressure, lipids, inflammation biomarkers, diabetes mellitus, alcohol consumption or socio-economic indicators.
Conclusion Adult height has directionally opposing relationships with risk of death from several different major causes of chronic diseases.
Height; cardiovascular disease; cancer; cause-specific mortality; epidemiological study; meta-analysis
To determine whether older age at graduation is associated with any difference in outcomes from the annual specialty training progression assessment.
An open cohort of 38 308 doctors who graduated from a UK medical school with annual assessments of progression in their specialty training programme with data centrally collected by the General Medical Council between 5 August 2009 to 31 July 2012.
Mature junior doctors (≥29 years at graduation) were more likely to have problems with progression on their annual review of competence progression record of in training assessment (ARCP/RITA) than their younger colleagues (OR 1.34, 95% CI 1.22 to 1.49, p<0.001). This association was, if anything, even stronger (OR 1.57, 95% CI 1.41 to 1.74, p<0.001) after adjustment for gender, ethnicity, type of University and specialty. The same was true when only looking at the most extreme ARCP outcome (4) which is being asked to leave their specialist programme (OR 1.81, 95% CI 1.34 to 2.44, p<0.001).
Mature doctors are a growing part of the medical workforce and they are likely to broaden the spectrum of doctors by bring different life experience to the profession. These results suggest that they are more likely to have problems with progressing through their specialist training programme. More research is required to determine the reasons behind these associations and how mature doctors can be supported both in choosing the best training programme and in coping with the complex demands of higher training at a later stage in their lives.
MEDICAL EDUCATION & TRAINING
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.
We previously used a single nucleotide polymorphism (SNP) in the CHRNA5-A3-B4 gene cluster associated with heaviness of smoking within smokers to confirm the causal effect of smoking in reducing body mass index (BMI) in a Mendelian randomisation analysis. While seeking to extend these findings in a larger sample we found that this SNP is associated with 0.74% lower body mass index (BMI) per minor allele in current smokers (95% CI -0.97 to -0.51, P = 2.00×10−10), but also unexpectedly found that it was associated with 0.35% higher BMI in never smokers (95% CI +0.18 to +0.52, P = 6.38×10−5). An interaction test confirmed that these estimates differed from each other (P = 4.95×10−13). This difference in effects suggests the variant influences BMI both via pathways unrelated to smoking, and via the weight-reducing effects of smoking. It would therefore be essentially undetectable in an unstratified genome-wide association study of BMI, given the opposite association with BMI in never and current smokers. This demonstrates that novel associations may be obscured by hidden population sub-structure. Stratification on well-characterized environmental factors known to impact on health outcomes may therefore reveal novel genetic associations.
We found that a single nucleotide polymorphism in the CHRNA5-A3-B4 gene cluster, which is known to influence smoking heaviness, is associated with lower body mass index (BMI) in current smokers, but higher BMI in never smokers. This difference in effects suggests that the variant influences BMI both via pathways other than smoking, and via the weight-reducing effects of smoking, in opposite directions. The overall effect on BMI would therefore be undetectable in an unstratified genome-wide association study, indicating that novel associations may be obscured by hidden population sub-structure.
Background. Haptoglobin acts as an antioxidant by limiting peroxidative tissue damage by free hemoglobin. The haptoglobin gene allele Hp2 comprises a 1.7 kb partial duplication. Relative to allele Hp1, Hp2 carriers form protein multimers, suboptimal for hemoglobin scavenging. Objective. To examine the association of haptoglobin genotype with a range of phenotypes, with emphasis on vitamin C and hemoglobin levels. Methods. We applied a quantitative PCR assay for the duplication junction to two population cohorts including 2747 British women and 1198 British men. We examined the association of haptoglobin duplicon copy number with hemoglobin and vitamin C and used the copy number to complete a phenome scan. Results. Hemoglobin concentrations were greater in those with Hp2,2 genotype, in women only (Hp1,1 13.45 g/dL, Hp1,2 13.49 g/dL, Hp2,2 13.61 g/dL; P = 0.002), though statistically there was no evidence of a difference between the sexes (z value = 1.2, P = 0.24). Haptoglobin genotype was not associated with vitamin C or any other phenotype in either cohort. Conclusions. Our results do not support association of haptoglobin genotype with vitamin C or with other phenotypes measured in two population cohorts. The apparent association between haptoglobin genotype and hemoglobin in the women's cohort merits further investigation.
The impact of Parkinson’s disease (PD) dementia is substantial and has major functional and socioeconomic consequences. Early prediction of future cognitive impairment would help target future interventions. The Montreal Cognitive Assessment (MoCA), the Mini-Mental State Examination (MMSE), and fluency tests were administered to 486 patients with PD within 3.5 years of diagnosis, and the results were compared with those from 141 controls correcting for age, sex, and educational years. Eighteen-month longitudinal assessments were performed in 155 patients with PD. The proportion of patients classified with normal cognition, mild cognitive impairment (MCI), and dementia varied considerably, depending on the MoCA and MMSE thresholds used. With the MoCA total score at screening threshold, 47.7%, 40.5%, and 11.7% of patients with PD were classified with normal cognition, MCI, and dementia, respectively; by comparison, 78.7% and 21.3% of controls had normal cognition and MCI, respectively. Cognitive impairment was predicted by lower education, increased age, male sex, and quantitative motor and non-motor (smell, depression, and anxiety) measures. Longitudinal data from 155 patients with PD over 18 months showed significant reductions in MoCA scores, but not in MMSE scores, with 21.3% of patients moving from normal cognition to MCI and 4.5% moving from MCI to dementia, although 13.5% moved from MCI to normal; however, none of the patients with dementia changed their classification. The MoCA may be more sensitive than the MMSE in detecting early baseline and longitudinal cognitive impairment in PD, because it identified 25.8% of those who experienced significant cognitive decline over 18 months. Cognitive decline was associated with worse motor and non-motor features, suggesting that this reflects a faster progressive phenotype.
Parkinson’s disease; mild cognitive impairment; dementia; Mini-Mental State Examination; Montreal Cognitive Assessment
To investigate whether associations of smoking with depression and anxiety are likely to be causal, using a Mendelian randomisation approach.
Mendelian randomisation meta-analyses using a genetic variant (rs16969968/rs1051730) as a proxy for smoking heaviness, and observational meta-analyses of the associations of smoking status and smoking heaviness with depression, anxiety and psychological distress.
Current, former and never smokers of European ancestry aged ≥16 years from 25 studies in the Consortium for Causal Analysis Research in Tobacco and Alcohol (CARTA).
Primary outcome measures
Binary definitions of depression, anxiety and psychological distress assessed by clinical interview, symptom scales or self-reported recall of clinician diagnosis.
The analytic sample included up to 58 176 never smokers, 37 428 former smokers and 32 028 current smokers (total N=127 632). In observational analyses, current smokers had 1.85 times greater odds of depression (95% CI 1.65 to 2.07), 1.71 times greater odds of anxiety (95% CI 1.54 to 1.90) and 1.69 times greater odds of psychological distress (95% CI 1.56 to 1.83) than never smokers. Former smokers also had greater odds of depression, anxiety and psychological distress than never smokers. There was evidence for positive associations of smoking heaviness with depression, anxiety and psychological distress (ORs per cigarette per day: 1.03 (95% CI 1.02 to 1.04), 1.03 (95% CI 1.02 to 1.04) and 1.02 (95% CI 1.02 to 1.03) respectively). In Mendelian randomisation analyses, there was no strong evidence that the minor allele of rs16969968/rs1051730 was associated with depression (OR=1.00, 95% CI 0.95 to 1.05), anxiety (OR=1.02, 95% CI 0.97 to 1.07) or psychological distress (OR=1.02, 95% CI 0.98 to 1.06) in current smokers. Results were similar for former smokers.
Findings from Mendelian randomisation analyses do not support a causal role of smoking heaviness in the development of depression and anxiety.
Mendelian randomisation; Smoking; Depression; Anxiety
Adult cognition and age-related cognitive decline can be influenced by dysregulation of the hypothalamic pituitary adrenal axis with concomitant changes in cortisol levels. However, very little is known about the role of childhood cognition and educational attainment in this relationship. Using data from the British 1946 birth cohort, the present study investigated: (1) associations between cortisol levels and patterns and cognitive function in midlife; (2) direct and interactive effects of childhood cognition, educational attainment and cortisol on cognitive function in midlife. Verbal memory, letter search speed and reaction time were assessed at age 60–64 years. Salivary cortisol samples (wakening, 30 min after wakening and evening) were collected at the same age. Childhood cognitive ability was measured at ages 8, 11, and 15, and educational level was reported at age 26. Associations between cortisol, childhood cognition, educational attainment and cognitive function in midlife were tested using linear regression and structural equation modelling approaches. Higher evening cortisol level was associated with slower reaction time and lower verbal memory. These associations were independent of childhood cognition and education as well as a range of other potential confounders. Childhood cognition and education were not directly associated with evening cortisol. However, there was a significant interaction effect between childhood cognition and evening cortisol on reaction time (p = .002): higher evening cortisol was associated with slower reaction time only among those with low childhood cognitive ability. There was little evidence of associations between the other cortisol measures and cognitive function.
Cognition; Development; Stress; Cortisol; Memory; Ageing
Experimental animal work shows that prenatal stress has a persisting effect on the Hypothalamic-Pituitary-Adrenal (HPA) axis of offspring. The implications of these findings for human health and development are not yet clear.
The data are based on the ALSPAC cohort, a prospective longitudinal study of a community sample that has followed mothers and children from pregnancy. When the children were aged 15 years, diurnal cortisol samples were collected at wake-up, 30 minutes post-awakening and at afternoon and evening times on up to three consecutive days on n=889 adolescents. Diurnal cortisol was predicted from prenatal anxiety and depression, obstetric, life-style, socio-demographic, and postnatal covariates.
Multilevel model analysis indicated that maternal prenatal anxiety was associated with a modest alteration of diurnal cortisol, indexed by a reduced cortisol awakening response and flatter diurnal slope. The effects were independent of psychosocial and obstetric covariates and measures of maternal postnatal anxiety; effects were similar for prenatal maternal depression. There was no association between adolescent cortisol and paternal prenatal anxiety.
There are small but persisting associations between maternal prenatal mood and diurnal cortisol in the child that persist into adolescence and may constitute a programming effect.
prenatal anxiety; HPA axis; ALSPAC; cortisol; developmental programming
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
The definition of Parkinson’s disease (PD) is changing with the expansion of clinical phenomenology and improved understanding of environmental and genetic influences that impact on the pathogenesis of the disease at the cellular and molecular level. This had led to debate and discussion with as yet, no general acceptance of the direction that change should take either at the level of diagnosis or of what should and should not be sheltered under an umbrella of PD. This article is one contribution to this on-going discussion. There are two different themes running through the article - widening the definition of PD/LBD/synucleinopathies and the heterogeneity that exists within PD itself from a clinical, pathological and genetic per-spective. The conclusion reached is that in the future, further diagnostic categories will need to be recognized. These are likely to include - Parkinson’s syndrome, Parkinson’s syndrome likely to be Lewy body PD, clinical PD (defined by QSBB criteria), Lewy body disease (PD, LBD, REM SBD) and synucleinopathies (including LBD, MSA).
Parkinson’s disease; phenomenology; aetiology; pathology; pathogenesis; synucleinopathies
Insulin-like growth factors are peptide hormones that have an endocrine role in the development, growth and repair of human tissues including the respiratory tract. To date, only one population study exists which found positive cross-sectional associations with IGF-I and higher lung volumes. We hypothesised that higher IGF-I, IGF-II, IGFBP-3 and IGF molar ratio would be associated with better cross-sectional and longitudinal lung function. We examined cross-sectional (n=843) and prospective associations (n=717) between IGF-I, IGF-II, IGFBP-3 and IGF molar ratio with lung function in the Caerphilly Prospective Study (CaPS) from blood samples obtained around 1986, with spirometry (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)) performed in the same year and around 2003. Higher IGF molar ratio was associated with improved FEV1/FEV ratio cross-sectionally in both simple (0.007, 95% CI 0.001-0.013, P=0.02) and fully adjusted (0.001, 95% CI 0.001-0.012, P=0.03) models. With the exception of IGFBP-3 and FEV1/FVC in the simple model (0.009, 95% CI 0.001-0.018, P=0.04) all prospective associations between IGF and spirometric measures were consistent with chance. In this study of men, higher IGF molar ratio was associated with improved cross-sectional lung function, although these findings were not replicated prospectively. Further work is required with repeat IGF sampling during follow up to see if IGF levels play any role in predicting future lung function through the life course.
Insulin-like growth factors; cohort study; spirometry; lung function
Background: Undernutrition and physical inactivity are both associated with lower bone mass.
Objective: This study aimed to investigate the combined effects of early-life undernutrition and urbanized lifestyles in later life on bone mass accrual in young adults from a rural community in India that is undergoing rapid socioeconomic development.
Design: This was a prospective cohort study of participants of the Hyderabad Nutrition Trial (1987–1990), which offered balanced protein-calorie supplementation to pregnant women and preschool children younger than 6 y in the intervention villages. The 2009–2010 follow-up study collected data on current anthropometric measures, bone mineral density (BMD) measured by dual-energy X-ray absorptiometry, blood samples, diet, physical activity, and living standards of the trial participants (n = 1446, aged 18–23 y).
Results: Participants were generally lean and had low BMD [mean hip BMD: 0.83 (women), 0.95 (men) g/cm2; lumbar spine: 0.86 (women), 0.93 (men) g/cm2]. In models adjusted for current risk factors, no strong evidence of a positive association was found between BMD and early-life supplementation. On the other hand, current lean mass and weight-bearing physical activity were positively associated with BMD. No strong evidence of an association was found between BMD and current serum 25-hydroxyvitamin D or dietary intake of calcium, protein, or calories.
Conclusions: Current lean mass and weight-bearing physical activity were more important determinants of bone mass than was early-life undernutrition in this population. In transitional rural communities from low-income countries, promotion of physical activity may help to mitigate any potential adverse effects of early nutritional disadvantage.
Laboratory tests are extensively used for diagnosis and monitoring in UK
primary care. Test usage by GPs, and associated costs, have grown
substantially in recent years.
This study aimed to quantify temporal growth and geographic variation in
utilisation of laboratory tests.
Design and setting
Retrospective cohort study using data from general practices in the UK.
Data from the General Practice Research Database, including patient
demographics, clinical details, and laboratory test results, were used to
estimate rates of change in utilisation between 2005 and 2009, and identify
tests with greatest inter-regional variation, by fitting random-effects
Poisson regression models. The study also investigated indications for test
requests, using diagnoses and symptoms recorded in the 2 weeks before each
Around 660 000 tests were recorded in 230 000 person-years of follow-up. Test
use increased by 24.2%, from 23 872 to 29 644 tests per 10 000
person-years, between 2005 and 2009. Tests with the largest increases were
faecal occult blood (121%) and C-reactive protein (86%).
There was substantial geographic variation in test utilisation; GPs in some
regions requested tests such as plasma viscosity and cardiac enzymes at a
rate more than three times the national average.
Increases in the use of laboratory tests have substantial resource
implications. Rapid increases in particular tests may be supported by
evidence-based guidelines, but these are often vague about who should be
tested, how often, and for how long. Substantial regional variation in test
use may reflect uncertainty about diagnostic accuracy and appropriate
indications for the laboratory test. There is a need for further research on
the diagnostic accuracy, therapeutic impact, and effect on patient health
outcomes of the most rapidly increasing and geographically variable
clinical laboratory techniques; economics; evidence-based medicine; physician practice patterns; primary health care; trends
Background At the APOE gene, encoding apolipoprotein E, genotypes of the ε2/ε3/ε4 alleles associated with higher LDL-cholesterol (LDL-C) levels are also associated with higher coronary risk. However, the association of APOE genotype with other cardiovascular biomarkers and risk of ischaemic stroke is less clear. We evaluated the association of APOE genotype with risk of ischaemic stroke and assessed whether the observed effect was consistent with the effects of APOE genotype on LDL-C or other lipids and biomarkers of cardiovascular risk.
Methods We conducted a systematic review of published and unpublished studies reporting on APOE genotype and ischaemic stroke. We pooled 41 studies (with a total of 9027 cases and 61 730 controls) using a Bayesian meta-analysis to calculate the odds ratios (ORs) for ischaemic stroke with APOE genotype. To better evaluate potential mechanisms for any observed effect, we also conducted a pooled analysis of primary data using 16 studies (up to 60 883 individuals) of European ancestry. We evaluated the association of APOE genotype with lipids, other circulating biomarkers of cardiovascular risk and carotid intima-media thickness (C-IMT).
Results The ORs for association of APOE genotypes with ischaemic stroke were: 1.09 (95% credible intervals (CrI): 0.84–1.43) for ε2/ε2; 0.85 (95% CrI: 0.78–0.92) for ε2/ε3; 1.05 (95% CrI: 0.89–1.24) for ε2/ε4; 1.05 (95% CrI: 0.99–1.12) for ε3/ε4; and 1.12 (95% CrI: 0.94–1.33) for ε4/ε4 using the ε3/ε3 genotype as the reference group. A regression analysis that investigated the effect of LDL-C (using APOE as the instrument) on ischaemic stroke showed a positive dose-response association with an OR of 1.33 (95% CrI: 1.17, 1.52) per 1 mmol/l increase in LDL-C. In the separate pooled analysis, APOE genotype was linearly and positively associated with levels of LDL-C (P-trend: 2 × 10−152), apolipoprotein B (P-trend: 8.7 × 10−06) and C-IMT (P-trend: 0.001), and negatively and linearly associated with apolipoprotein E (P-trend: 6 × 10−26) and HDL-C (P-trend: 1.6 × 10−12). Associations with lipoprotein(a), C-reactive protein and triglycerides were non-linear.
Conclusions In people of European ancestry, APOE genotype showed a positive dose-response association with LDL-C, C-IMT and ischaemic stroke. However, the association of APOE ε2/ε2 genotype with ischaemic stroke requires further investigation. This cross-domain concordance supports a causal role of LDL-C on ischaemic stroke.
Stroke; lipids; apolipoprotein E; cardiovascular disease; systematic review; meta-analysis; biomarkers
Parkinson's disease (PD) is the second most common neurodegenerative disease affecting 1–2% in people >60 and 3–4% in people >80. Genome-wide association (GWA) studies have now implicated significant evidence for association in at least 18 genomic regions. We have studied a large PD-meta analysis and identified a significant excess of SNPs (P < 1 × 10−16) that are associated with PD but fall short of the genome-wide significance threshold. This result was independent of variants at the 18 previously implicated regions and implies the presence of additional polygenic risk alleles. To understand how these loci increase risk of PD, we applied a pathway-based analysis, testing for biological functions that were significantly enriched for genes containing variants associated with PD. Analysing two independent GWA studies, we identified that both had a significant excess in the number of functional categories enriched for PD-associated genes (minimum P = 0.014 and P = 0.006, respectively). Moreover, 58 categories were significantly enriched for associated genes in both GWA studies (P < 0.001), implicating genes involved in the ‘regulation of leucocyte/lymphocyte activity’ and also ‘cytokine-mediated signalling’ as conferring an increased susceptibility to PD. These results were unaltered by the exclusion of all 178 genes that were present at the 18 genomic regions previously reported to be strongly associated with PD (including the HLA locus). Our findings, therefore, provide independent support to the strong association signal at the HLA locus and imply that the immune-related genetic susceptibility to PD is likely to be more widespread in the genome than previously appreciated.
In the present study, we examined the associations of early nutrition with adult lean body mass (LBM) and muscle strength in a birth cohort that was established to assess the long-term impact of a nutrition program. Participants (n = 1,446, 32% female) were born near Hyderabad, India, in 29 villages from 1987 to 1990, during which time only intervention villages (n = 15) had a government program that offered balanced protein-calorie supplementation to pregnant women and children. Participants’ LBM and appendicular skeletal muscle mass were measured using dual energy x-ray absorptiometry; grip strength and information on lifestyle indicators, including diet and physical activity level, were also obtained. Ages (mean = 20.3 years) and body mass indexes (weight (kg)/height (m)2; mean = 19.5) of participants in 2 groups were similar. Current dietary energy intake was higher in the intervention group. Unadjusted LBM and grip strength were similar in 2 groups. After adjustment for potential confounders, the intervention group had lower LBM (β = −0.75; P = 0.03), appendicular skeletal muscle mass, and grip strength than did controls, but these differences were small in magnitude (<0.1 standard deviation). Multivariable regression analyses showed that current socioeconomic position, energy intake, and physical activity level had a positive association with adult LBM and muscle strength. This study could not detect a “programming” effect of early nutrition supplementation on adult LBM and muscle strength.
body composition; cohort study; developmental origins of health and disease; grip strength; lean body mass; muscle mass; nutrition; physical activity
Some studies have found an association between elevated cortisol and subsequent depression, but findings are inconsistent. The cortisol awakening response may be a more stable measure of hypothalamic-pituitary-adrenal function and potentially of stress reactivity.
To investigate whether salivary cortisol, particularly the cortisol awakening response, is associated with subsequent depression in a large population cohort.
Young people (aged 15 years, n = 841) from the Avon Longitudinal Study of Parents and Children (ALSPAC) collected salivary cortisol at four time points for 3 school days. Logistic regression was used to calculate odds ratios for developing depression meeting ICD-10 criteria at 18 years.
We found no evidence for an association between salivary cortisol and subsequent depression. Odds ratios for the cortisol awakening response were 1.24 per standard deviation (95% CI 0.93-1.66, P = 0.14) before and 1.12 (95% CI 0.73-1.72, P = 0.61) after adjustment for confounding factors. There was no evidence that the other cortisol measures, including cortisol at each time point, diurnal drop and area under the curve, were associated with subsequent depression.
Our findings do not support the hypothesis that elevated salivary cortisol increases the short-term risk of subsequent depressive illness. The results suggest that if an association does exist, it is small and unlikely to be of clinical significance.
Tourette syndrome and chronic tic disorder are heritable but aetiologically complex. Although environment plays a role in their development, existing studies of non-genetic risk factors are inconsistent.
To examine the association between pre- and perinatal exposures and Tourette syndrome/chronic tic disorder in the Avon Longitudinal Study of Parents and Children (ALSPAC) prospective longitudinal pre-birth cohort.
Relationships between exposures and Tourette syndrome/chronic tic disorder were examined in 6090 children using logistic regression.
Maternal alcohol and cannabis use, inadequate maternal weight gain and parity were associated with Tourette syndrome or Tourette syndrome/chronic tic disorder. Other previously reported exposures, including birth weight and prenatal maternal smoking, were not associated with Tourette syndrome/chronic tic disorder.
This study supports previously reported relationships between Tourette syndrome/chronic tic disorder and prenatal alcohol exposure, and identifies additional previously unexplored potential prenatal risk factors.
Healthy lifestyles based on non-smoking, an acceptable BMI, a high fruit and vegetable intake, regular physical activity, and low/moderate alcohol intake, are associated with reductions in the incidence of certain chronic diseases, but to date there is limited evidence on cognitive function and dementia.
In 1979 healthy behaviours were recorded on 2,235 men aged 45–59 years in Caerphilly, UK. During the following 30 years incident diabetes, vascular disease, cancer and death were recorded, and in 2004 cognitive state was determined.
Men who followed four or five of the behaviours had an odds ratio (OR) and confidence intervals (CI) for diabetes, corrected for age and social class, of 0.50 (95% CI: 0.19, 1.31; P for trend with increasing numbers of healthy behaviours <0.0005). For vascular disease the OR was 0.50 (95% CI: 0.30, 0.84; P for trend <0.0005), and there was a delay in vascular disease events of up to 12 years. Cancer incidence was not significantly related to lifestyle although there was a reduction associated with non-smoking (OR: 0.65; 95% CI: 0.54, 0.79). All-cause mortality was reduced in men following four or five behaviours (OR 0.40; 95% CI: 0.24, 0.67; P for trend <0.005).
After further adjustment for NART, the OR for men following four or five healthy behaviours was 0.36 (95% CI: 0.12, 1.09; P for trend <0.001) for cognitive impairment, and 0.36 (95% CI: 0.07, 1.99; P for trend <0.02) for dementia.
The adoption of a healthy lifestyle by men was low and appears not to have changed during the subsequent 30 years, with under 1% of men following all five of the behaviours and 5% reporting four or more in 1979 and in 2009.
A healthy lifestyle is associated with increased disease-free survival and reduced cognitive impairment but the uptake remains low.
Gait impairment is common in people with Parkinson’s disease. There is a lack of effective interventions to target this debilitating complication and therefore a need to identify new therapeutic options. An underlying cholinergic deficit contributes to both the gait and cognitive dysfunction seen in Parkinson’s disease. The combined impact of both impairments can be assessed in gait tasks performed with concomitant cognitive tasks. The aim of this trial is to evaluate the impact of a cholinesterase inhibitor on cognitive function and gait performance in people with established Parkinson’s disease.
This is a single centre, double-blind, randomised placebo-controlled trial in 130 people with Hoehn and Yahr stage 2–3 idiopathic Parkinson’s disease who have fallen in the past year. Participants will be randomised to two groups, receiving either rivastigmine capsules or identical placebo capsules for 8 months. Assessment will be undertaken at baseline and at the end of medication prescription (i.e. 8 months) with participants remaining enrolled in the trial for a further 4 months to monitor for falls and adverse events. The primary outcome is step time variability, assessed with and without the addition of concurrent cognitive tasks. Secondary outcomes will include other gait parameters, sensorimotor and balance performances, cognitive indices, falls and fall related injury, fear of falling, Parkinson’s symptoms and data pertaining to possible harms.
This randomised controlled trial will examine the effect of cholinesterase inhibitor therapy on gait, balance and falls in Parkinson’s disease. If effective, it would offer a new therapeutic option to ameliorating gait and cognitive deficits in a population at high risk of falls.
ISRCTN19880883, UTN U1111-1124-0244.
Randomised control trial; Parkinson’s disease; Accidental Falls; Freezing of gait; Intervention; Gait analysis; Acetylcholinesterase; Cognitive; Attention; Dual-tasking
Background: studies have shown that milk and dairy consumption in adulthood have beneficial effects on health.
Methods: we examined the impact of childhood and adult diet on physical performance at age 63–86 years. The Boyd Orr cohort (n = 405) is a 65-year prospective study of children who took part in a 1930's survey; the Caerphilly Prospective Study (CaPS; n = 1,195) provides data from mid-life to old age. We hypothesised that higher intakes of childhood and adult milk, calcium, protein, fat and energy would be associated with a better performance.
Results: in fully adjusted models, a standard deviation (SD) increase in natural log-transformed childhood milk intake was associated with 5% faster walking times from the get-up and go test in Boyd Orr (95% CI: 1 to 9) and 25% lower odds of poor balance (OR: 0.75; 0.55 to 1.02). Childhood calcium intake was positively associated with walking times (4% faster per SD; 0 to 8) and a higher protein intake was associated with lower odds of poor balance (OR: 0.71; 0.54 to 0.92). In adulthood, protein intake was positively associated with walking times (2% faster per SD; 1 to 3; Boyd Orr and CaPS pooled data).
Conclusion: this is the first study to show positive associations of childhood milk intake with physical performance in old age.
diet; physical performance; walking speed; standing balance; older people
Social isolation may operate as a psychosocial stressor which disrupts functioning of the hypothalamic–pituitary–adrenocortical axis.
Using data from the MRC National Survey of Health and Development, we tested whether living alone, not being married and social network size were associated with diurnal cortisol patterns at 60–64 years. We hypothesised that recent onset compared with long-term isolation would be more strongly associated with cortisol awakening response, cortisol decline over the day and evening cortisol. Models were adjusted for sex, smoking, body mass index, alcohol intake, psychological distress and financial difficulties.
Those widowed within the last three years had a 36% (95%CI 6%, 73%) higher night time cortisol than those who were currently married. Those newly living alone also had a higher night time cortisol and flatter diurnal slope than those living with others.
Independently of multiple behavioural and psychosocial correlates, recent onset of social isolation is related to diurnal cortisol patterns that increase the risk of morbidity and mortality.
NSHD; Psychosocial; HPA axis; Bereavement; Social isolation
Urban migration is associated with an increased risk of hypertension, obesity and diabetes in Indian migrants. This study assessed the relationship between internal migration and renal function in the Hyderabad arm of the Indian Migration Study.
We assessed 841 subjects; urban non-migrants (n = 158), urban migrants (n = 424) and rural non-migrants (n = 259). Muscle mass was ascertained from DXA scanning. We derived urban life years for urban migrants and rural non-migrants. Multivariable linear regression was used to examine the association between tertiles of urban life years and 4-variable MDRD eGFR using Stata 11.
Mean eGFR was lower in urban non-migrants and urban migrants compared to rural non-migrants. The prevalence of CKD 3-5 was higher in the rural non-migrant population (5.0%) than in the urban non-migrant populations (2.5%) due to a negatively skewed distribution of eGFR in rural non-migrants. As urban life years increased, eGFR declined (p = 0.008) though there was no obvious dose response effect. After adjustment for muscle mass, the association was attenuated and the trend was consistent with chance (p = 0.08). Further adjustment for vascular risk factors weakened the association to a small degree (p = 0.11).
The high prevalence of reduced eGFR in rural areas requires further research. Urbanization was associated with reduced eGFR. This association appears mostly to be due to higher muscle mass with a small contribution from adverse vascular disease risk factors.