The association of prenatal alcohol exposure on the cognitive abilities and behaviour profiles of 4-year-old children: a prospective cohort study.

OBJECTIVE: To examine the association of prenatal alcohol exposure (PAE) on cognitive abilities and behaviour profiles of 4-year-old children. DESIGN: Prospective cohort study. SETTING: Cape Town, South Africa. POPULATION: A cohort of 500 children. METHODS: Children from the Safe Passage Study, which prospectively collected PAE, were included. Cognition and behavioural profiles were assessed. Children with and without PAE were compared. Mean scores were compared, with P ≤ 0.05 considered significant. Results were adjusted for confounding factors. MAIN OUTCOME MEASURES: The Kaufman Assessment Battery for children measured intellectual and mental ability; the NEPSY-II instrument assessed neurocognitive performance. The caregiver completed the Preschool Child Behaviour checklist to rate the child's problem behaviours and competencies. RESULTS: Two hundred children had no PAE, 117 children had mild to moderate PAE (with no binge episodes), 113 children had heavy PAE (with one or two binge episodes), and 70 children had very heavy PAE (with three or more binge episodes). Women who binge drank had significantly higher rates of smoking, marijuana use, and methamphetamine use. Low to moderate PAE had no effect on cognitive ability and behaviour. Very heavy PAE was associated with problems performing simultaneous as well as sequential functions, lower scores in the language and sensorimotor domain, and more attention and pervasive developmental problems. CONCLUSIONS: Low to moderate PAE was not associated with cognitive processing or developmental problems. Women who had many binge drinking episodes during pregnancy were the most at risk for cognitive processing, neurocognitive, and behaviour problems in their children at 4 years of age. TWEETABLE ABSTRACT: Low to moderate prenatal alcohol use was not associated with cognitive or behavioural problems in 4-year-olds.

Winter growth phenology and leaf orientation in Pachypodium namaquanum (Apocynaceae) in the succulent karoo of the Richtersveld, South Africa.

Pachypodium namaquanum (Nyley ex Harb.) Welw., an unusual arborescent stem succulent from the succulent karoo of the arid Richtersveld in north-western South Africa and adjacent Namibia, is characterized by a striking curvature of the terminal 20-60 cm of the trunk toward the north. This orientation displays the single terminal whorl of drought-deciduous leaves with their flat surface angled at a mean inclination of 55° from horizontal. Inclination of 50-60° was found in 65% of individuals sampled, and 85% were inclined between 45 and 65°. Northward azimuth was also quite regular, but varied slightly between populations. The fixed leaf orientation in P. namaquanum maximizes radiation absorption during the winter months when leaves are present. Leaves normally form in early fall (April) and abscise early in spring (October). Growing season conditions in the Richtersveld are relatively mild, with mean maximum temperature dropping only to 21.6°C in July, the coldest month of the year. Frosts are rare. By the fixed orientation of its leaf whorl, P. namaquanum is able to maintain nearly twice the midwinter radiation absorptance that it would have with horizontal orientation. Over an annual cycle the angled leaves receive more radiation than would horizontal leaves for each of the 6 months in which they are present on the plant. This increased winter irradiance is hypothesized to singificantly increase net primary production by concentrating growth activities in winter months and allowing the species to remain dormant during the hyperarid conditions of the hot summer months. Midwinter flowering from apical buds in P. namaquanum may also be aided by its stem orientation. The evolution of this characteristic pattern of winter growth phenology and nodding stem orientation may have come about because of low but relatively regular autumn precipitation and moderate winter temperatures. Slow and regular growth of P. namaquanum leads to long lifespans which may reach 300 years or more.