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Growth in early infancy drives optimal brain functional connectivity which predicts cognitive flexibility in later childhood.
Bulgarelli, C, Blasi, A, McCann, S, Milosavljevic, B, Ghillia, G, Mbye, E, Touray, E, Fadera, T, Acolatse, L, Moore, SE, et al
bioRxiv : the preprint server for biology. 2024
Abstract
Functional brain network organization, measured by functional connectivity (FC), reflects key neurodevelopmental processes for healthy development. Early exposure to adversity, e.g. undernutrition, affects neurodevelopment, observable via disrupted FC, and leads to poorer outcomes from preschool age onward. We assessed longitudinally the impact of early growth trajectories on developmental FC in a rural Gambian population from age 5 to 24 months. To investigate how these early trajectories relate to later childhood outcomes, we assessed cognitive flexibility at 3-5 years. We observed that early physical growth before the fifth month of life drove optimal developmental trajectories of FC that in turn predicted cognitive flexibility at pre-school age. In contrast to previously studied developmental populations, this Gambian sample exhibited long-range interhemispheric FC that decreased with age. Our results highlight the measurable effects that poor growth in early infancy has on brain development and the subsequent impact on pre-school age cognitive development, underscoring the need for early life interventions throughout global settings of adversity.
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It takes a village: Caregiver diversity and language contingency in the UK and rural Gambia.
Katus, L, Crespo-Llado, MM, Milosavljevic, B, Saidykhan, M, Njie, O, Fadera, T, McCann, S, Acolatse, L, Perapoch Amadó, M, Rozhko, M, et al
Infant behavior & development. 2024;:101913
Abstract
INTRODUCTION There is substantial diversity within and between contexts globally in caregiving practices and family composition, which may have implications for the early interaction's infants engage in. We draw on data from the Brain Imaging for Global Health (BRIGHT, www.globalfnirs.org/the-bright-project) project, which longitudinally examined infants in the UK and in rural Gambia, West Africa. In The Gambia, households are commonly characterized by multigenerational, frequently polygamous family structures, which, in part, is reflected in the diversity of caregivers a child spends time with. In this paper, we aim to 1) evaluate and validate the Language Environment Analysis (LENA) for use in the Mandinka speaking families in The Gambia, 2) examine the nature (i.e., prevalence of turn taking) and amount (i.e., adult and child vocalizations) of conversation that infants are exposed to from 12 to 24 months of age and 3) investigate the link between caregiver diversity and child language outcomes, examining the mediating role of contingent turn taking. METHOD We obtained naturalistic seven-hour-long LENA recordings at 12, 18 and 24 months of age from a cohort of N = 204 infants from Mandinka speaking households in The Gambia and N = 61 infants in the UK. We examined developmental changes and site differences in LENA counts of adult word counts (AWC), contingent turn taking (CTT) and child vocalizations (CVC). In the larger and more heterogenous Gambian sample, we also investigated caregiver predictors of turn taking frequency. We hereby examined the number of caregivers present over the recording day and the consistency of caregivers across two subsequent days per age point. We controlled for children's cognitive development via the Mullen Scales of Early Learning (MSEL). RESULTS Our LENA validation showed high internal consistency between the human coders and automated LENA outputs (Cronbach's alpha's all >.8). All LENA counts were higher in the UK compared to the Gambian cohort. In The Gambia, controlling for overall neurodevelopment via the MSEL, CTT at 12 and 18 months predicted CVC at 18 and 24 months. Caregiver consistency was associated with CTT counts at 18 and 24 months. The number of caregivers and CTT counts showed an inverted u-shape relationship at 18 and 24 months, with an intermediate number of caregivers being associated with the highest CTT frequencies. Mediation analyses showed a partial mediation by number of caregivers and CTT and 24-month CVC. DISCUSSION The LENA provided reliable estimates for the Mandinka language in the home recording context. We showed that turn taking is associated with subsequent child vocalizations and explored contextual caregiving factors contributing to turn taking in the Gambian cohort.
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Breast Milk Micronutrients and Infant Neurodevelopmental Outcomes: A Systematic Review.
Lockyer, F, McCann, S, Moore, SE
Nutrients. 2021;(11)
Abstract
Micronutrients are fundamental for healthy brain development and deficiencies during early development can have a severe and lasting impact on cognitive outcomes. Evidence indicates that undernourished lactating individuals may produce breast milk containing lower concentrations of certain vitamins and minerals. Exclusively breastfed infants born to mothers deficient in micronutrients may therefore be at risk of micronutrient deficiencies, with potential implications for neurodevelopment. This systematic review aims to consider current knowledge on the effects of breast milk micronutrients on the developmental outcomes of infants. The databases Medline, Global Health, PsychInfo, Open Grey, and the Web of Science were searched for papers published before February 2021. Studies were included if they measured micronutrients in breast milk and their association with the neurodevelopmental outcomes of exclusively breastfed infants. Also, randomised control trials investigating neurocognitive outcomes following maternal supplementation during lactation were sought. From 5477 initial results, three observational studies were eligible for inclusion. These investigated associations between breast milk levels of vitamin B6, carotenoids, or selenium and infant development. Results presented suggest that pyroxidal, β-carotene, and lycopene are associated with infant neurodevelopmental outcomes. Limited eligible literature and heterogeneity between included papers prevented quantitative synthesis. Insufficient evidence was identified, precluding any conclusions on the relationship between breast milk micronutrients and infant developmental outcomes. Further, the evidence available was limited by a high risk of bias. This highlights the need for further research in this area to understand the long-term influence of micronutrients in breast milk, the role of other breast milk micronutrients in infant neurodevelopmental outcomes, and the impact of possible lactational interventions.
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The Role of Iron in Brain Development: A Systematic Review.
McCann, S, Perapoch Amadó, M, Moore, SE
Nutrients. 2020;12(7)
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Plain language summary
Iron deficiency is the most common vitamin or mineral deficiency worldwide and is particularly common among pregnant women, infants and young children due to high iron demands during periods of rapid growth. Iron plays an important role in the development of the brain, and animal studies suggest that getting enough iron in pregnancy and early childhood is particularly important. The aims of this systematic review were to (i) investigate the relationship between iron status and brain development and (ii) assess whether this relationship differs according to age or type of development (‘domain’). The researchers looked for studies on iron deficiency or iron supplementation in pregnancy and up to 4 years of age. 26 observational studies and 28 intervention studies were included in the review. There was no clear relationship between iron status and developmental outcomes across any of the ages or domains included. Many of the studies were of low quality and there was a wide variation in study design, along with a lack of research on pregnancy and early infancy. The researchers concluded that evidence for the impact of iron deficiency or iron supplementation on early development is inconsistent. Further high-quality research is needed, particularly within pregnancy and early infancy, which has previously been neglected.
Abstract
One-third of children falter in cognitive development by pre-school age. Iron plays an important role in many neurodevelopmental processes, and animal studies suggest that iron sufficiency in pregnancy and infancy is particularly important for neurodevelopment. However, it is not clear whether iron deficiency directly impacts developmental outcomes, and, if so, whether impact differs by timing of exposure or developmental domain. We searched four databases for studies on iron deficiency or iron supplementation in pregnancy, or at 0-6 months, 6-24 months, or 2-4 years of age. All studies included neurodevelopmental assessments in infants or children up to 4 years old. We then qualitatively synthesized the literature. There was no clear relationship between iron status and developmental outcomes across any of the time windows or domains included. We identified a large quantity of low-quality studies, significant heterogeneity in study design and a lack of research focused on pregnancy and early infancy. In summary, despite good mechanistic evidence for the role of iron in brain development, evidence for the impact of iron deficiency or iron supplementation on early development is inconsistent. Further high-quality research is needed, particularly within pregnancy and early infancy, which has previously been neglected.
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Valproate, bipolar disorder and polycystic ovarian syndrome.
McIntyre, RS, Mancini, DA, McCann, S, Srinivasan, J, Kennedy, SH
Bipolar disorders. 2003;(1):28-35
Abstract
BACKGROUND Persons with bipolar disorder are often overweight and cluster risk factors for cardiovascular disease. Some antibipolar agents adversely impact upon weight and the lipid milieu. Recent data suggest that valproic acid, a commonly prescribed mood stabilizer, may be associated with polycystic ovarian syndrome (PCOS). This adverse event has not been systematically studied in bipolar disorder. METHOD Thirty-eight female subjects, aged 18-50 years, meeting DSM-IV criteria for bipolar I or II disorder, in any phase of illness were evaluated. Eighteen females received valproate (sodium valproate and valproic acid) and 20 females received lithium. Patients completed questions regarding their menstrual, reproductive and medical histories. During the follicular phase they were assessed for weight, body mass index (BMI kg/m2), and changes in the reproductive endocrine milieu that included morning estradiol, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex-hormone binding globulin (SHBG), androstenedione, dehydroepiandrosterone-sulfate (DHEAS), testosterone, free testosterone, prolactin and thyroid-stimulating hormone (TSH). The blood was also analyzed for fasting metabolic parameters which included total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), insulin, glycosylated hemoglobin (HbA1C), insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding-protein 1 (IGFBP-1), fasting blood glucose and morning leptin. RESULTS Nine (50%) of the valproate-treated females had menstrual abnormalities versus three (15%) of the lithium-treated females (p < 0.05). Valproate-treated females had significantly higher levels of follicular phase androgen concentrations than lithium-treated females (p < 0.05). Nine (50%) of females who were overweight (BMI > or = 25 kg/m2) and with a history of menstrual irregularities also exhibited laboratory evidence of hyperandrogenism (p < 0.05). Persons receiving valproate exhibited significant increases in fasting biochemical parameters suggestive of an adverse metabolic syndrome (p < 0.05). Leptin levels were significantly elevated in the valproate-treated females (p < 0.05). CONCLUSIONS In this pilot, open-label cross-sectional study, valproate-treated females exhibited higher rates of menstrual abnormalities and biochemical evidence of both hyperandrogenism and adverse metabolic parameters when compared with lithium-treated females. These preliminary data suggest that valproate may, in some predisposed females, adversely impact upon the reproductive endocrine milieu and result in aspects of the metabolic syndrome.