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Ian J Deary

Publications and source records attributed to Ian J Deary.

At least 37 records · Page 2Linked to original sources
PubMed2006

Effects of acute hypoglycemia on motivation and cognitive interference in people with type 1 diabetes.

AIMS: To examine the effect of acute hypoglycemia on motivation and cognitive interference in adult humans with type 1 diabetes. METHODS: A hyperinsulinemic glucose clamp was used to either maintain euglycemia (arterialized blood glucose 4.5 mmol/L) or induce hypoglycemia (2.6 mmol/L) in 16 adults with type 1 diabetes, each of whom were studied on 2 separate occasions in a counterbalanced order. During each study condition, the subjects completed parallel tests of cognitive function. The Dundee Stress State Questionnaire (DSSQ) was administered before and after the cognitive function tests. RESULTS: Hypoglycemia decreased task-relevant (P = 0.03) and increased task-irrelevant (P = 0.02) interference. Self-focus of attention was much higher after hypoglycemia than euglycemia (P = 0.02). Motivation declined to a similar extent during the euglycemia and hypoglycemia conditions (P = 0.07). Hypoglycemia produced a negative mood state with a significant fall in energy levels (P = 0.03) and a concomitant rise in anxiety level (P = 0.05). The subjective perception of concentration was unaffected during hypoglycemia (P = 0.14), and the scores for control and confidence did not fall (P = 0.19). CONCLUSIONS: In people with type 1 diabetes, hypoglycemia causes a state of heightened self-awareness and distraction during active mental activity. This is likely to leave fewer processing resources available to allow completion of cognitive tasks. Acute hypoglycemia induces a state of significant worry and anxiety that is likely to affect the social, personal, and work activities of people with diabetes.

Affect↗
PubMed2006

Ankle brachial index as a predictor of cognitive impairment in the general population: ten-year follow-up of the Edinburgh Artery Study.

OBJECTIVES: To determine whether the ankle brachial index (ABI, a marker of generalized atherosclerosis) is associated with cognitive impairment after 10 years in older people. DESIGN: Cohort study (Edinburgh Artery Study). SETTING: Eleven general practices in Edinburgh, Scotland. PARTICIPANTS: Seven hundred seventeen men and women aged 55 to 74 from the general population, followed for 10 years. MEASUREMENTS: ABI measured at baseline and major cognitive functions (including premorbid function using the National Adult Reading Test, NART) tested after 10 years. RESULTS: After adjustment for age and sex, a low ABI was associated with lower scoring (bottom tertile vs top tertile) on Raven's Matrices (odds ratio (OR)=1.6, 95% confidence interval (CI) =1.0-2.6), Verbal Fluency (OR =1.8, 95% CI =1.1-3.0), and Digit Symbol Test (OR =2.3, 95% CI =1.3-4.2), suggesting that the ABI is predictive of poorer performance in nonverbal reasoning, verbal fluency, and information processing speed. The association between ABI and the Digit Symbol Test remained significant after further adjustment for premorbid cognitive function (tested using the NART), suggesting that the ABI is also predictive of decline in information processing speed (from premorbid ability to that measured here in older age). CONCLUSION: The ABI may be useful in identifying older individuals at higher risk of cognitive impairment. In the future, preventive measures developed to target individuals with a low ABI should consider measures to reduce vascular-related cognitive decline as well as cardiovascular events, in an effort to reduce the incidence and consequences of subsequent cognitive impairment and dementia.

Aged↗
PubMed2006

Childhood IQ and life course socioeconomic position in relation to alcohol induced hangovers in adulthood: the Aberdeen children of the 1950s study.

OBJECTIVE: To examine the association between scores on IQ tests in childhood and alcohol induced hangovers in middle aged men and women. DESIGN, SETTING, AND PARTICIPANTS: A cohort of 12 150 people born in Aberdeen (Scotland) who took part in a school based survey in 1962 when IQ test scores were extracted from educational records. Between 2000 and 2003, 7184 (64%) responded to questionnaire inquiries regarding drinking behaviour. MAIN OUTCOME MEASURES: Self reported hangovers attributable to alcohol consumption on two or more occasions per month. RESULTS: Higher IQ scores at 11 years of age were associated with a lower prevalence of hangovers in middle age (OR(per one SD advantage in IQ score); 95% CI: 0.80; 0.72, 0.89). This relation was little affected by adjustment for childhood indicators of socioeconomic position (0.82; 0.74, 0.91) but was considerably attenuated after control for adult variables (fully adjusted model: 0.89; 0.79, 1.01). CONCLUSIONS: Higher childhood IQ was related to a lower prevalence of alcohol induced hangovers in middle aged men and women. The IQ-hangover effect may at least partially explain the link between early life IQ and adult mortality. This being the first study to examine this relation, more evidence is required.

Adult↗
PubMed2006

Sex differences in cognitive abilities test scores: a UK national picture.

BACKGROUND AND AIMS: There is uncertainty about the extent or even existence of sex differences in the mean and variability of reasoning test scores ( Jensen, 1998; Lynn, 1994, ; Mackintosh, 1996). This paper analyses the Cognitive Abilities Test (CAT) scores of a large and representative sample of UK pupils to determine the extent of any sex differences. SAMPLE: A nationally representative UK sample of over 320,000 school pupils aged 11-12 years was assessed on the CAT (third edition) between September 2001 and August 2003. The CAT includes separate nationally standardized tests for verbal, quantitative, and non-verbal reasoning. The size and recency of the sample is unprecedented in research on this issue. METHODS: The sheer size of the sample ensures that any sex difference will achieve statistical significance. Therefore, effect sizes (d) and variance ratios (VR) are employed to evaluate the magnitude of sex differences in mean scores and in score variability, respectively. RESULTS: The mean verbal reasoning score for girls was 2.2 standard score points higher than the mean for boys, but only 0.3 standard points in favour of girls for non-verbal reasoning (NVR), and 0.7 points in favour of boys for quantitative reasoning (QR). However, for all three tests there were substantial sex differences in the standard deviation of scores, with greater variance among boys. Boys were over represented relative to girls at both the top and the bottom extremes for all tests, with the exception of the top 10% in verbal reasoning. CONCLUSIONS: Given the small differences in means, explanations for sex differences in wider domains such examination attainment at age 16 need to look beyond conceptions of 'ability'. Boys tend to be both the lowest and the highest performers in terms of their reasoning abilities, which warns against the danger of stereotyping boys as low achievers.

Achievement↗
PubMed2006

Effect of maternal smoking during pregnancy on offspring's cognitive ability: empirical evidence for complete confounding in the US national longitudinal survey of youth.

BACKGROUND: Numerous studies have reported that maternal cigarette smoking during pregnancy is related to lower IQ scores in the offspring. Confounding is a crucial issue in interpreting this association. METHODS: In the US National Longitudinal Survey of Youth 1979, IQ was ascertained serially during childhood using the Peabody Individual Achievement Test, the total score for which comprises results on 3 subtests: mathematics, reading comprehension, and reading recognition. Maternal IQ was assessed by using the Armed Forces Qualification Test. There were 5578 offspring (born to 3145 mothers) with complete information for maternal smoking habits, total Peabody Individual Achievement Test score, and covariates. RESULTS: The offspring of mothers who smoked > or = 1 pack of cigarettes per day during pregnancy had an IQ score (Peabody Individual Achievement Test total) that was, on average, 2.87 points lower than children born to nonsmoking mothers. Separate control for maternal education (0.27-IQ-point decrement) and, to a lesser degree, maternal IQ (1.51-IQ-point decrement) led to marked attenuation of the maternal-smoking-offspring-IQ relation. A similar pattern of results was seen when Peabody Individual Achievement Test subtest results were the outcomes of interest. The only exception was the Peabody Individual Achievement Test mathematics score, in which adjusting for maternal IQ essentially led to complete attenuation of the maternal-smoking-offspring-IQ gradient (0.66-IQ-point decrement). The impact of controlling for physical, behavioral, and other social indices was much less pronounced than for maternal education or IQ. CONCLUSIONS: These findings suggest that previous studies that did not adjust for maternal education and/or IQ may have overestimated the association of maternal smoking with offspring cognitive ability.

Adolescent↗
PubMed2005

Relationship between lifetime smoking, smoking status at older age and human cognitive function.

Cigarette smoking is a major risk factor for clinical cardiovascular disease and may also be associated with poorer cognitive functioning in older age. We measured lifetime cigarette smoking, smoking status and cognitive function in over 2,000 men and women from the general population aged over 50 years with subclinical atherosclerosis (ankle brachial pressure index<or=0.95 but no history of clinical cardiovascular disease). In this population, an association was found between greater lifetime smoking and poorer cognitive function in men and between smoking cessation and better cognitive function in women. The former relationship appeared to reflect an association between smoking habit and prior cognitive function (in early life), whereas the latter remained significant after adjustment for tests of crystallised cognitive function, suggesting a relationship between continuing to smoke (as opposed to quitting) and age-related cognitive decline. Both relationships were independent of the degree of atherosclerosis (as measured using the ankle brachial pressure index), suggesting alternative underlying mechanisms for the association between smoking and human adult cognitive function.

Aged↗
PubMed2005

Polymorphisms in the gene encoding 11B-hydroxysteroid dehydrogenase type 1 (HSD11B1) and lifetime cognitive change.

A rare polymorphism in the gene encoding 11B-hydroxysteroid dehydrogenase type 1 (HSD11B1: rs846911-C/A) has been associated with an increased risk of Alzheimer's disease. We tested the hypothesis that this and 2 other HSD11B1 polymorphisms (rs12086634-G/T and rs846910-A/G) were associated with lifetime cognitive change in humans. Subjects were 194 participants of the Scottish Mental Survey of 1932 who took the same well-validated mental test at age 11 and age 79. The subjects represented the highest and lowest quintiles with respect to cognitive decline between ages 11 and 79. Despite having non-significantly different IQs at age 11, by age 79 the groups had mean (S.D.) IQs of 80.3 (14.1) and 109.6 (9.1), respectively (p<.001). The polymorphism rs846911-C/A was absent from both groups. There were no significant differences in the frequency of polymorphisms of rs12086634-G/T (p=.91) and rs846910-A/G (p=.90) between the groups. We conclude that these variants in HSD11B1 are not significant contributors to the range of cognitive ageing examined here.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMed2005

Genetic influences on oxidative stress and their association with normal cognitive ageing.

Oxidative stress is hypothesised to play a major role in ageing processes. Reactive oxygen species produced during normal aerobic metabolism damage cellular macromolecules. The brain is particularly susceptible to oxidative stress due to its high rate of aerobic metabolism. We hypothesised that polymorphisms in genes contributing to antioxidant defences are associated with variation in normal cognitive ageing in the absence of dementia. We examined associations between two SNPs (rs2073495 and rs743658) in Lactotransferrin (LTF), a gene involved in iron absorption, and the common M129V SNP in the prion protein gene, PRNP (rs1799990), with cognitive ability and cognitive ageing in a cohort of non-demented individuals born in 1921. All had cognitive ability measured at age 11 in the Scottish Mental Survey of 1932, and again at age 79. No association was identified with LTF. PRNP M129V was significantly related to Moray House Test (MHT) IQ scores at age 79, adjusted for sex and age 11 IQ (p=0.006). Individuals homozygous for the methionine allele performed significantly better than heterozygotes. This study supports the hypothesis that genetic variations in antioxidant defence genes, specifically PRNP, are important influences on the trajectory of normal cognitive ageing. An interaction between PRNP and klotho (KL) genotypes was also identified (p=0.015), highlighting the importance of analysing gene interactions when investigating associations with quantitative traits.

Aged↗
PubMed2005

Retinal image analysis: concepts, applications and potential.

As digital imaging and computing power increasingly develop, so too does the potential to use these technologies in ophthalmology. Image processing, analysis and computer vision techniques are increasing in prominence in all fields of medical science, and are especially pertinent to modern ophthalmology, as it is heavily dependent on visually oriented signs. The retinal microvasculature is unique in that it is the only part of the human circulation that can be directly visualised non-invasively in vivo, readily photographed and subject to digital image analysis. Exciting developments in image processing relevant to ophthalmology over the past 15 years includes the progress being made towards developing automated diagnostic systems for conditions, such as diabetic retinopathy, age-related macular degeneration and retinopathy of prematurity. These diagnostic systems offer the potential to be used in large-scale screening programs, with the potential for significant resource savings, as well as being free from observer bias and fatigue. In addition, quantitative measurements of retinal vascular topography using digital image analysis from retinal photography have been used as research tools to better understand the relationship between the retinal microvasculature and cardiovascular disease. Furthermore, advances in electronic media transmission increase the relevance of using image processing in 'teleophthalmology' as an aid in clinical decision-making, with particular relevance to large rural-based communities. In this review, we outline the principles upon which retinal digital image analysis is based. We discuss current techniques used to automatically detect landmark features of the fundus, such as the optic disc, fovea and blood vessels. We review the use of image analysis in the automated diagnosis of pathology (with particular reference to diabetic retinopathy). We also review its role in defining and performing quantitative measurements of vascular topography, how these entities are based on 'optimisation' principles and how they have helped to describe the relationship between systemic cardiovascular disease and retinal vascular changes. We also review the potential future use of fundal image analysis in telemedicine.

Animals↗
PubMed2005

Effect of axial length on retinal vascular network geometry.

PURPOSE: To explore the association between axial length and retinal vascular network geometry (arteriovenous diameter ratio [AVR], arteriolar branching angles, and junctional exponents). DESIGN: Prospective, cross-sectional study. METHODS: Patients were recruited from a pseudophakic population that had preexisting axial length measurements. Mean arterial blood pressure and previous medical history were recorded. Fundal photographs were taken. Digital image analysis was used to determine the AVR, mean arteriolar bifurcation angle, and junctional exponent for each subject. RESULTS: In total, 52 subjects were analyzed. Axial length had no association with AVR (R = -0.01, P = .941), mean angles at arteriolar bifurcations (R = -.134, P = .342), or junctional exponents (R = .003, P = .982). However, increased axial length was associated with a trend for lower measured retinal venular and arteriolar diameters (R = -.28, P = .04 and R = -.23, P = .10, respectively). Junctional exponents correlated with both the AVR (R = .32, P = .019) and vascular bifurcation angles (omega) (R = .317, P = .022). CONCLUSIONS: Increased axial length is associated with narrowing of both arteriolar and venular diameters, but not on the AVR, or vessel junctions. Future studies exploring the influence of systemic disease on retinal vascular topography do not need to consider axial length as a potential confounding variable when utilizing measures such as AVR or vessel junctions. Vascular arteriolar junctional exponents may serve as a good measure of overall altered retinal vascular geometry in cardiovascular disease.

Adult↗
PubMed2005

The functional COMT polymorphism, Val 158 Met, is associated with logical memory and the personality trait intellect/imagination in a cohort of healthy 79 year olds.

A polymorphism (Val 158 Met) in the gene for catechol-O-methyl transferase (COMT) was previously associated with differences in cognitive ability and personality. Here we examine associations between this polymorphism and cognitive ability, cognitive aging, personality and mood in 460 relatively healthy people born in 1921. All had cognitive ability measured at age 11 in the Scottish Mental Survey of 1932, and again at age 79. COMT genotype was not associated with childhood IQ. At age 79, COMT genotype was significantly related to differences in verbal declarative memory (scores on the Logical Memory test; p=0.028) and to scores on the personality trait of intellect/imagination (p=0.023), adjusted for sex and childhood IQ. In both cases the Val/Met heterozygotes had higher scores than both homozygous groups. There were trends toward the heterozygotes having higher scores on the personality traits of agreeableness and conscientiousness. The effect of COMT genotype on Logical Memory scores was independent of the effect of APOE genotype, and similar in effect size. Therefore, COMT genotype may contribute to differences in normal cognitive aging and to differences in some of the major personality traits in old age.

Aged↗
PubMed2005

Brain white matter hyperintensities: relative importance of vascular risk factors in nondemented elderly people.

PURPOSE: To prospectively determine whether there is an association between brain white matter signal hyperintensities on magnetic resonance (MR) images and potential risk factors for cerebral ischemia in a well-characterized narrow age cohort of nondemented community-dwelling elderly people. MATERIALS AND METHODS: The study population consisted of surviving members of the Aberdeen 1921 Birth Cohort, a subsample of participants in the 1932 Scottish Mental Survey who were born in 1921. With the permission of the local ethics committee and with informed written consent, 106 nondemented subjects (62 men, 44 women) aged 78-79 years underwent T2-weighted brain MR imaging. Brain MR images were scored semiquantitatively for deep white matter hyperintensities and periventricular hyperintensities. Vascular risk factors and clinical measures potentially associated with cerebral ischemia included hypertension, diabetes, cerebrovascular disease, smoking, body mass index grade, respiratory function levels (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and peak expiratory flow rate [PEFR]) normalized for subject's height, plasma lipid levels (cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein), glycated hemoglobin level, and mean fasting blood glucose level. Pearson correlation coefficients were calculated for correlations between potential vascular risk factors and scores for deep white matter and periventricular hyperintensities, and stepwise multiple linear regression analysis was performed for factors with a statistically significant correlation. RESULTS: Significant Pearson correlations with deep white matter hyperintensities were found for glycated hemoglobin level (r = 0.31), hypertension (r = 0.27), normalized FEV1 (r = -0.27), normalized FVC (r = -0.22), normalized PEFR (r = -0.27), low-density lipoprotein (r = 0.24), and cholesterol (r = 0.20), and with periventricular hyperintensities for glycated hemoglobin level (r = 0.28) and normalized PEFR (r = -0.23). Multiple linear regression analysis showed that glycated hemoglobin level and hypertension were predictive of 16.2% of the variance in deep white matter hyperintensities. When subjects with non-insulin-dependent (type 2) diabetes mellitus (n = 11) were excluded, hypertension and decreased normalized PEFR were predictive of 11.7% of the variance. CONCLUSION: White matter hyperintensities are associated with elevated levels of glycated hemoglobin in nondemented community-dwelling elderly subjects. Hypertension and decreased normalized PEFR are the principal predictors of deep white matter hyperintensities in nondiabetic subjects.

Aged↗
PubMed2005

Growth in early life and childhood IQ at age 11 years: the Newcastle Thousand Families Study.

BACKGROUND: It has been suggested that in addition to genetic factors, fetal and post-natal growth influence childhood cognition, although it is unclear whether such an effect continues throughout childhood. This study aimed at investigating the potential relationships between childhood IQ at age 11 years and birth weight and height at the ages of 9 and 13 years, after adjusting for the confounding factors available to this investigation. METHODS: The Newcastle Thousand Families study, a prospectively followed cohort, originally consisted of all 1142 births in the city of Newcastle in May and June 1947. Using data on 733 members of this cohort, we investigated the associations between IQ at age 11, and birth weight and height at ages 9 and 13 years. RESULTS: Birth weight showed no association with childhood IQ. However, height at age 9 years was a significant predictor of childhood IQ after adjusting for socioeconomic status (standardized regression coefficient b = 2.6, 95% CI 1.6-3.6, P < 0.0001). Height at age 13 was also a significant predictor of IQ after adjusting for socioeconomic status (b = 3.4, 95% CI 2.3-4.4, P = 0.001), and explained an additional 2.5% of the variation in IQ scores to that already explained by socioeconomic status and height at age nine. CONCLUSIONS: These results suggest a continuing effect of post-natal growth on childhood cognition beyond the age of 9 years. Post-natal growth, which may be influenced by genetic factors and nutrition and socioeconomic circumstances in childhood, may be more important than fetal growth in terms of childhood cognition.

Adolescent↗
PubMed2005

Plasma cortisol levels, brain volumes and cognition in healthy elderly men.

PURPOSE: In ageing animals, exposure to chronic high levels of glucocorticoids is associated with cognitive impairment and hippocampal atrophy. However, there are few studies examining relationships among glucocorticoids, brain volumes and cognitive function in healthy older humans. This study examined the hypotheses that higher plasma cortisol levels and altered sensitivity to glucocorticoids are associated with worse cognition and more brain atrophy in elderly men. MATERIALS AND METHODS: Ninety-seven healthy men aged 65-70 had plasma cortisol measured at 09:00, 14:30 h, and post-dexamethasone (0.25mg, 09:00 h), and had dermal sensitivity to glucocorticoids measured. They also underwent cognitive testing, with scores adjusted for estimated prior mental ability, and had MRI measurements of intracranial area (a validated estimate of intracranial capacity), and hippocampus, temporal lobe and frontal lobe volumes. RESULTS: Plasma cortisol levels at 09:00 h were significantly and negatively correlated with a summary General Cognitive Factor accounting for 51% of the variance of cognitive function (rho=-0.22, p=0.035), and specific cognitive tests: delayed paragraph recall (rho=-0.28, p=0.036) and processing speed (rho=-0.23, p=0.026). Regional brain volumes adjusted for intracranial area generally did not correlate with cortisol levels. Tissue glucocorticoid sensitivity did not correlate with any measure of cognition or brain volume. CONCLUSIONS: In healthy older men, higher plasma cortisol levels are associated with worse ageing-related overall cognitive change but not ageing-related brain atrophy.

Aged↗