People who score poorly in intellectual ability tests have shorter life expectancy. A study was undertaken to determine whether this association is different in people from different socioeconomic backgrounds.
The mortality of 2786 men born in Helsinki, Finland during 1934-1944 who, as military conscripts, underwent a standardised intellectual ability test comprising verbal, visuospatial and arithmetic reasoning subtests was studied. Mortality data came from the Finnish Death Register.
Comparing men in the lowest and highest test score quartiles, HRs for all-cause mortality were 1.9 (95% CI 1.4 to 2.5) for verbal reasoning, 2.2 (95% CI 1.6 to 3.0) for visuospatial reasoning and 1.9 (95% CI 1.4 to 2.5) for arithmetic reasoning, corresponding to 2.6, 3.4 and 2.6 excess years of life lost, respectively. Associations were similar for cardiovascular and non-cardiovascular mortality. Intellectual ability scores were stronger predictors in men who grew up in middle-class families. Compared with middle-class men in the highest quartile of the visuospatial reasoning score, middle-class men in the lowest quartile lost 6.5 years of life while men from families of manual workers in the highest quartile lost 2.8 years and men in the lowest quartile lost 5.6 years.
High intellectual ability in men aged 20 protects them from mortality in later life. This effect is stronger in men who grew up in middle-class families than in those who grew up in manual worker families. This finding suggests that early life conditions that are unfavourable to the development of cognitive abilities negate the life expectancy benefits of being born into a more affluent family.
Cites: Cogn Psychol. 2000 Aug;41(1):1-4810945921
Cites: Am J Epidemiol. 2009 Aug 15;170(4):447-5519528290
Cites: BMJ. 2001 Apr 7;322(7290):81911290633
Cites: BMJ. 2001 Apr 21;322(7292):949-5311312225
Cites: BMJ. 2001 Dec 1;323(7324):1273-611731388
Cites: J Epidemiol Community Health. 2003 Sep;57(9):681-612933773
To examine whether the adverse effects of slow prenatal and postnatal growth on cognitive function persist to old age and predict age related cognitive decline.
A longitudinal birth cohort study of men born in Helsinki, Finland 1934-44.
Nine-hundred-thirty-one men of the Helsinki Birth Cohort Study, with detailed data on growth from birth to adulthood, aged 20.1 (SD = 1.4) at the first and 67.9 (SD = 2.5) years at the second cognitive testing.
The Finnish Defense Forces Basic Intellectual Ability Test assessed twice over nearly five decades apart.
Lower weight, length and head circumference at birth were associated with lower cognitive ability at 67.9 years (1.04-1.55 points lower ability per each standard deviation [SD] unit decrease in body size, 95% Confidence Interval [95%CI]: 0.05 to 2.72) and with cognitive decline after 20.1 years (0.07-0.11 SD decline over time per each SD decrease in body size, 95%CI:0.00 to 0.19). Men who were born larger were more likely to perform better in the cognitive ability test over time (1.22-1.43 increase in odds to remain in the top relative to the lower two thirds in ability over time per each SD increase in body size, 95%CI:1.04 to 1.79) and were more resilient to cognitive decline after 20.1 years (0.69 to 0.76 decrease in odds to decline from than remain in the top third of ability over time per each SD increase in body size, 95%CI:0.49 to 0.99). Slower growth between birth and two years in weight, height and body mass index was associated with lower cognitive ability at 67.9 years, but not with cognitive decline.
Poorer lifetime cognitive ability is predicted by slower growth before and after birth. In predicting resilience to age related cognitive decline, the period before birth seems to be more critical.
Cites: Int J Epidemiol. 2002 Apr;31(2):342-811980795
Slow childhood growth is associated with poorer intellectual ability. The critical periods of growth remain uncertain. Among 2,786 Finnish male military conscripts (1952-1972) born in 1934-1944, the authors tested how specific growth periods from birth to age 20 years predicted verbal, visuospatial, and arithmetic abilities at age 20. Small head circumference at birth predicted poorer verbal, visuospatial, and arithmetic abilities. The latter 2 measures were also associated with lower weight and body mass index (weight (kg)/height (m)(2)) at birth (for a 1-standard-deviation (SD) decrease in test score per SD decrease in body size > or = 0.05, P's or = 0.05, P's
We tested whether maternal hypertensive disorders in pregnancy predict age-related change in cognitive ability in the offspring up to old age.
Using mothers' blood pressure and urinary protein measurements from the maternity clinics and birth hospitals, we defined normotensive or hypertensive pregnancies in mothers of 398 men, who participated in the Helsinki Birth Cohort 1934-1944 Study. The men underwent the Finnish Defence Forces basic ability test twice: first during compulsory military service at age 20.1 (SD = 1.4) years and then in a retest at age 68.5 (SD = 2.9) years. The test yields a total score and subscores for tests measuring verbal, arithmetic, and visuospatial reasoning.
Men born after pregnancies complicated by a hypertensive disorder, compared with men born after normotensive pregnancies, scored 4.36 (95% confidence interval, 1.17-7.55) points lower on total cognitive ability at 68.5 years and displayed a greater decline in total cognitive ability (2.88; 95% confidence interval, 0.07-5.06) after 20.1 years. Of the subscores, associations were strongest for arithmetic reasoning.
Maternal hypertensive disorders in pregnancy predict lower cognitive ability and greater cognitive decline up to old age. A propensity to lower cognitive ability and decline up to old age may have prenatal origins.
Cites: Ann Med. 2012 Jun;44(4):394-40321495787
Cites: Am J Obstet Gynecol. 2000 Jul;183(1):S1-S2210920346
Cites: BMJ. 2001 Apr 21;322(7292):949-5311312225
Cites: Asia Pac J Clin Nutr. 2002;11 Suppl 3:S537-4212492645
Cites: Am J Psychiatry. 2005 Oct;162(10):1904-1016199837
Hypertensive disorders may affect the fetal developmental milieu and thus hint at mechanisms by which prenatal adversity associates with poorer intellectual ability in subsequent life.
We tested if hypertensive disorders in pregnancy are associated with intellectual ability in the offspring in young adulthood and if any potential associations between hypertensive disorders and intellectual abilities differ according to length of gestation, birth-weight, parity, and childhood socio-economic background.
Using mothers' blood pressure and urinary protein measurements at maternity clinics and birth hospitals, we defined normotensive or hypertensive pregnancies in mothers of 1,196 men who participated in the Helsinki Birth Cohort 1934-1944 Study. At age 20 years the men completed a test on intellectual abilities during compulsory military service.
Participants born after pregnancies complicated by hypertensive disorders scored lower on intellectual abilities compared to those born after normotensive pregnancies. The effects of hypertensive disorders were most obvious in men born preterm or after a primiparous pregnancy and in men of higher childhood socio-economic background.
Hypertensive disorders in pregnancy are, albeit weakly, associated with lower intellectual abilities in the offspring. These findings are compatible with the concept of adverse fetal 'programming' by a suboptimal prenatal environment.
Diabetes Prevention Unit, Department of Health Promotion and Chronic Disease Prevention, National Institute for Health and Welfare, Mannerheimintie 166, 00300, Helsinki, Finland. email@example.com
The aim of this study is to assess whether intellectual ability in young adult men predicts the development of type 2 diabetes in later life. 641 men participating in the Helsinki Birth Cohort Study were administered a 2-h (75 g) oral glucose tolerance test at a mean age of 61 years. Intellectual ability was assessed during compulsory military service at a mean age of 20 years. Associations were explored using linear and logistic regression models. Intellectual ability in young adulthood did not predict glucose tolerance at age 61 years. However, educational attainment was associated with the prevalence of type 2 diabetes, independently of early intellectual ability. Men with the highest educational attainment were less likely to have type 2 diabetes than men with the lowest educational attainment (OR = 0.50, 95% CI 0.28-0.91). While education seems to protect from type 2 diabetes, we could not detect a connection between early intellectual ability and impairment in glucose regulation in later adulthood.
Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland Keski-Suomen Magneettikuvaus, Jyväskylä, Finland Department of Medical Rehabilitation, Oulu University Hospital and Institute of Health Sciences, University of Oulu, Oulu, Finland Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland Department of Public Health and Institute of Molecular Medicine, University of Helsinki, Helsinki, Finland Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland.
Exercise is thought to increase the diameter of the conduit arteries supplying the muscles involved. We studied the effects of a physically active vs inactive lifestyle on artery diameters in monozygotic (MZ) twin pairs discordant over 30 years for leisure-time physical activity habits. In a population-based co-twin control study design, six middle-aged (50-65 years) same-sex MZ twin pairs with long-term discordance for physical activity were comprehensively identified from the Finnish Twin Cohort (TWINACTIVE study). Discordance was initially defined in 1975 and the same co-twin remained significantly more active during the 32-year follow-up. The main outcomes were arterial lumen diameters measured from maximal intensity projections of contrast-enhanced MR angiography images. Paired differences between active and inactive co-twins were studied. Compared with inactive members, active members of MZ twin pairs had larger diameters for the distal aorta and iliac and femoral arteries (P0.2 for all comparisons) were found in the dimensions of the carotid arteries. Our genetically controlled study confirms that habitual physical activity during adulthood enlarges arteries in a site-specific manner.
Exercise is thought to reduce high-risk body fat, but intervention studies are frequently limited by short follow-ups and observational studies by genetic selection. Therefore, we studied the effects of a physically inactive vs active lifestyle on high-risk (visceral, liver and intramuscular) fat in twin pairs discordant for leisure-time physical activity habits for over 30 years.
A longitudinal population-based twin study.
Sixteen middle-aged (50-74 years) same-sex twin pairs (seven monozygotic (MZ), nine dizygotic (DZ)) with long-term discordance for physical activity habits were comprehensively identified from the Finnish Twin Cohort (TWINACTIVE study). Discordance was initially defined in 1975 and the same co-twin remained significantly more active during the 32-year-long follow-up.
Magnetic resonance imaging-assessed visceral, liver and intramuscular fat.
In within-pair analyses carried out after the adult life-long discordance in physical activity habits, the physically inactive co-twins had 50% greater visceral fat area compared with the active co-twins (mean difference 55.5 cm2, 95% confidence interval (CI) 7.0-104.1, P=0.010). The liver fat score was 170% higher (13.2, 95% CI 3.5-22.8, P=0.030) and the intramuscular fat area 54% higher (4.9 cm2, 95% CI 1.9-7.9, P=0.002) among the inactive co-twins. All the trends were similar for MZ and DZ pairs. Peak oxygen uptake was inversely associated with visceral (r=-0.46, P=0.012) and intramuscular fat area (r=-0.48, P=0.028), with similar trends in intrapair difference correlations (r=-0.57, P=0.021 and r=-0.50, P=0.056, respectively). The intrapair difference correlation between visceral and intramuscular fat was also high (r=0.65, P=0.009).
Regular physical activity seems to be an important factor in preventing the accumulation of high-risk fat over time, even after controlling for genetic liability and childhood environment. Therefore, the prevention and treatment of obesity should emphasize the role of regular leisure-time physical activity.
Long-term persistent physical activity is important in the prevention of chronic diseases, but a large number of people do not participate in physical activity to obtain health benefits. The purpose of this study was to examine the motives and perceived barriers to long-term engagement in leisure time physical activity. Same-sex twin pairs (N=16, mean age 60) discordant for physical activity over 30 years were identified from the Finnish Twin Cohort. We evaluated participants' physical activity motivation with the 73-item Recreational Exercise Motivation Measure and assessed barriers to physical activity with a 25-item questionnaire. The characteristics of physical activity motivation and perceived barriers between the active and inactive co-twins were analysed using paired tests. Motives related to the sub-dimensions of enjoyment and physical fitness and psychological state were the most important reasons for participation in physical activity among all the twin individuals analysed. The sub-dimensions mastery (p=0.018, Cohen's d=0.76), physical fitness (p=0.029, Cohen's d=0.69), and psychological state (p=0.039, Cohen's d=0.65) differed significantly between active and inactive co-twins. More than half of the participants reported no reasons for not being physically active. If reasons existed, participation in physical activity was deterred mostly by pain and various health problems. This study found no differences in perceived barriers between active and inactive co-twins. We conclude from our results that the main factors promoting persistent leisure time physical activity were participants' wish to improve or maintain their physical skills or techniques, a feeling that exercise would improve their mental and physical health and that they found the activity enjoyable. This study helps us understand the importance of the role of motives and the minor role of perceived barriers for engagement in persistent physical activity.
Low intellectual ability is associated with an increased risk of coronary heart disease and stroke. Most studies have used a general intelligence score. We studied whether three different subscores of intellectual ability predict these disorders.
We studied 2,786 men, born between 1934 and 1944 in Helsinki, Finland, who as conscripts at age 20 underwent an intellectual ability test comprising verbal, visuospatial (analogous to Raven's progressive matrices) and arithmetic reasoning subtests. We ascertained the later occurrence of coronary heart disease and stroke from validated national hospital discharge and death registers.
281 men (10.1%) had experienced a coronary heart disease event and 131 (4.7%) a stroke event. Coronary heart disease was predicted by low scores in all subtests, hazard ratios for each standard deviation (SD) lower score ranging from 1.21 to 1.30 (confidence intervals 1.08 to 1.46). Stroke was predicted by a low visuospatial reasoning score, the corresponding hazard ratio being 1.23 (95% confidence interval 1.04 to 1.46), adjusted for year and age at testing. Adjusted in addition for the two other scores, the hazard ratio was 1.40 (1.10 to 1.79). This hazard ratio was little affected by adjustment for socioeconomic status in childhood and adult life, whereas the same adjustments attenuated the associations between intellectual ability and coronary heart disease. The associations with stroke were also unchanged when adjusted for systolic blood pressure at 20 years and reimbursement for adult antihypertensive medication.
Stroke is predicted by low visuospatial reasoning scores in relation to scores in the two other subtests. This association may be mediated by common underlying causes such as impaired brain development, rather than by mechanisms associated with risk factors shared by stroke and coronary heart disease, such as socio-economic status, hypertension and atherosclerosis.
Cites: J Epidemiol Community Health. 2010 Oct;64(10):908-1219833609
Cites: Eur Heart J. 2009 Aug;30(15):1903-919602715