Association between birthweight and cognitive function in middle age: the atherosclerosis risk in communities study

Birthweight, gestational age, and early school trajectory

BACKGROUND

Birthweight and gestational age are important factors of not only newborn health by also child development and can contribute to delayed cognitive abilities. However, no study has analyzed the association of birthweight and gestational age with school trajectory measured simultaneously by school entry, grade repetition, and school dropout. This study aims, first, to analyze the association of birthweight or gestational age with school entry, and second, to explore the relationship between birthweight or gestational age and grade repetition and school dropout among children in Ouagadougou, Burkina Faso.

METHODS

This study used longitudinal data from the Ouagadougou Health and Demographic Surveillance System. Our samples consisted of children born between 2008 and 2014 who were at least three years old at the beginning of the 2017-18 school year. Samples included 13,676, 3152, and 3498 children for the analysis of the school entry, grade repetition, and dropout, respectively. A discrete-time survival model was used to examine the relationship between birthweight or gestational age and school entry, grade repetition, and dropout. The association between birthweight or gestational age and age at school entry were assessed using a Poisson regression.

RESULTS

The incidence rate of school entry was 18.1 per 100 people-years. The incidence of first repetition and dropout were 12.6 and 5.9, respectively. The probability of school entry decreased by 31% (HR:0.69, 95%CI: 0.56-0.85) and 8% (HR:0.92, 95%CI: 0.85-0.99) for children weighing less than 2000 g and those weighing between 2000 and 2499 g, respectively, compared to those born with a normal weight (weight ≥ 2500 g). The age at school entry of children with a birthweight less than 2000 g and between 2000 and 2499 g was 7% (IRR: 1.07, 95%CI: 1.06-1.08) and 3% (IRR: 1.03, 95%CI: 1.00-1.06) higher than children born at a normal birthweight, respectively. Gestational age was not associated with school entry or age at school entry. Similarly, birthweight and gestational age were not associated with grade repetition or dropout.

CONCLUSION

This study shows that low birthweight is negatively associated with school entry and age at school entry in Ouagadougou. Efforts to avoid low birthweights should be part of maternal and prenatal health care because the associated difficulties may be difficult to overcome later in the child's life. Further longitudinal studies are needed to better understand the relationship between development at birth and school trajectory.

Size at birth, lifecourse factors, and cognitive function in late life: findings from the MYsore study of Natal effects on Ageing and Health (MYNAH) cohort in South India

OBJECTIVE

To examine if smaller size at birth, an indicator of growth restriction in utero, is associated with lower cognition in late life, and whether this may be mediated by impaired early life brain development and/or adverse cardiometabolic programming.

DESIGN

Longitudinal follow-up of a birth cohort.

SETTING

CSI Holdsworth Memorial Hospital (HMH), Mysore South India.

PARTICIPANTS

721 men and women (55-80 years) whose size at birth was recorded at HMH. Approximately 20 years earlier, a subset (n = 522) of them had assessments for cardiometabolic disorders in mid-life.

MEASUREMENTS

Standardized measurement of cognitive function, depression, sociodemographic, and lifestyle factors; blood tests and assessments for cardiometabolic disorders.

RESULTS

Participants who were heavier at birth had higher composite cognitive scores (0.12 SD per SD birth weight [95% CI 0.05, 0.19] p = 0.001) in late life. Other lifecourse factors independently positively related to cognition were maternal educational level and participants' own educational level, adult leg length, body mass index, and socioeconomic position, and negatively were diabetes in mid-life and current depression and stroke. The association of birth weight with cognition was independent cardiometabolic risk factors and was attenuated after adjustment for all lifecourse factors (0.08 SD per SD birth weight [95% CI -0.01, 0.18] p = 0.07).

CONCLUSIONS

The findings are consistent with positive effects of early life environmental factors (better fetal growth, education, and childhood socioeconomic status) on brain development resulting in greater long-term cognitive function. The results do not support a pathway linking poorer fetal development with reduced late life cognitive function through cardiometabolic programming.

Size at birth and cognitive ability in late life: A systematic review

INTRODUCTION

Recent evidence suggests that growth restriction in utero may lead to neurocognitive disorders in late life, either through impaired brain development or adverse metabolic programming.

METHODS

Systematic review of literature investigating the relationship between size at birth and cognitive abilities in late life. The search, data extraction, and rating for the quality of reporting were conducted independently by two researchers.

RESULTS

Of 533 selected studies, 11 were included in this systematic review and 10 of these were from high-income setting. Of these 11 studies, eight indicated that lower birth weight is a risk factor for lower cognitive function in late life, at least in high-income countries. The reported effect sizes were small and it was not possible to conduct meta-analyses because of clinical heterogeneity DISCUSSION: A modest association of lower birth weight with lower cognitive abilities in late life is consistent with persisting effects of the prenatal environment on brain function. As with all observational studies, confounding is an alternative explanation. Further studies are required to elucidate the mechanisms.

The Effect of Prenatal and Childhood Development on Hearing, Vision and Cognition in Adulthood

It is unclear what the contribution of prenatal versus childhood development is for adult cognitive and sensory function and age-related decline in function. We examined hearing, vision and cognitive function in adulthood according to self-reported birth weight (an index of prenatal development) and adult height (an index of early childhood development). Subsets (N = 37,505 to 433,390) of the UK Biobank resource were analysed according to visual and hearing acuity, reaction time and fluid IQ. Sensory and cognitive performance was reassessed after ~4 years (N = 2,438 to 17,659). In statistical modelling including age, sex, socioeconomic status, educational level, smoking, maternal smoking and comorbid disease, adult height was positively associated with sensory and cognitive function (partial correlations; pr 0.05 to 0.12, p < 0.001). Within the normal range of birth weight (10^th to 90^th percentile), there was a positive association between birth weight and sensory and cognitive function (pr 0.06 to 0.14, p < 0.001). Neither adult height nor birth weight was associated with change in sensory or cognitive function. These results suggest that adverse prenatal and childhood experiences are a risk for poorer sensory and cognitive function and earlier development of sensory and cognitive impairment in adulthood. This finding could have significant implications for preventing sensory and cognitive impairment in older age.

Birth weight and cognitive function in early adulthood: the Australian Aboriginal birth cohort study

It has been suggested that in addition to genetic factors, fetal and post-natal growth influence cognition in early adulthood. However, most studies have been in developed populations, so it is unclear if the same findings would be seen in other, less developed, settings, and have used testing tools not applicable to an Australia Aboriginal population. This study investigated the relationships between cognitive function in early adulthood and birth weight and contemporary height. Simple reaction time (SRT), choice reaction time (CRT) and working memory (WM) were assessed using the CogState battery. A significant association was seen between birth weight and SRT in early adulthood, but not with the other two cognitive measures. Urban dwellers had significantly shorter SRT and CRT than their remote counterparts. Contemporary body mass index and maternal age were associated with CRT. Only fetal growth restriction was associated with WM, with greater WM in those with restricted growth. No associations were seen with contemporary height. These results suggest that fetal growth may be more important than the factors influencing post-natal growth in terms of cognition in early adulthood in this population, but that the associations may be inconsistent between cognitive outcomes. Further research is required to identify whether similar associations are seen in other, similar, populations and to assess why differences in cognitive outcome measures are seen.

Early life origins cognitive decline: findings in elderly men in the Helsinki Birth Cohort Study

OBJECTIVES

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.

DESIGN AND SETTING

A longitudinal birth cohort study of men born in Helsinki, Finland 1934-44.

PARTICIPANTS

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.

MAIN OUTCOME MEASURES

The Finnish Defense Forces Basic Intellectual Ability Test assessed twice over nearly five decades apart.

RESULTS

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.

CONCLUSIONS

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.