Maternal smoking during pregnancy and offspring intellectual disability: sibling analysis in an intergenerational Danish cohort

Background Maternal smoking has known adverse effects on fetal development. However, research on the association between maternal smoking during pregnancy and offspring intellectual disability (ID) is limited, and whether any associations are due to a causal effect or residual confounding is unknown. Method Cohort study of all Danish births between 1995 and 2012 (1 066 989 persons from 658 335 families after exclusions), with prospectively recorded data for cohort members, parents and siblings. We assessed the association between maternal smoking during pregnancy (18.6% exposed, collected during prenatal visits) and offspring ID (8051 cases, measured using ICD-10 diagnosis codes F70–F79) using logistic generalised estimating equation regression models. Models were adjusted for confounders including measures of socio-economic status and parental psychiatric diagnoses and were adjusted for family averaged exposure between full siblings. Adjustment for a family averaged exposure allows calculation of the within-family effect of smoking on child outcomes which is robust against confounders that are shared between siblings. Results We found increased odds of ID among those exposed to maternal smoking in pregnancy after confounder adjustment (OR 1.35, 95% CI 1.28–1.42) which attenuated to a null effect following adjustment for family averaged exposure (OR 0.91, 95% CI 0.78–1.06). Conclusions Our findings are inconsistent with a causal effect of maternal smoking during pregnancy on offspring ID risk. By estimating a within-family effect, our results suggest that prior associations were the result of unmeasured genetic or environmental characteristics of families in which the mother smokes during pregnancy.

Variasi Pertumbuhan dan Estimasi Parameter Genetik Semai Nyawai (Ficus variegata Blume)

Growth variation and genetic parameter estimation of Ficus variegata Blume seedlings were done at The Centre for Forest Biotechnology and Tree Improvement, Yogyakarta at 8 months of age. Genetic materials from Banyuwangi population which comprised of 15 families and Cilacap-Pangandaran population comprised of 19 families. The trial was designed as a Randomized Completely Block Design (RCBD) with family as treatment, 3 replications and each replication comprises 10 seedlings. The purpose of this study was to observe growth variation and genetic parameter of these populations at seedlings level. Analysis of variance was performed to find out family effect on height and diameter traits. Analysis of variance component was used to estimate coefficient of genetic variation, heritability and genetic correlation. This study showed that family effect on height and diameter variation was very significant at both populations. The estimation of coefficient of genetic variation for height and diameter trait ranged from 10.80% (categorized as intermediate) to 18.04% (categorized as high). Family heritability estimation for height trait ranged from 0.96 to 0.99 and diameter trait ranged from 0.89 to 0.96, both categorized as high. Strong genetic correlation for height and diameter trait ranged from 0.87 to 0.89.Keywords: Nyawai, Ficus variegata, growth, genetic parameter, seedling.

Actual and intended growth in family firms and non-family-owned firms: are they different?

Purpose Drawing on the motivation theory and family business literature, the purpose of this paper is to investigate the influence of family effect in growth behaviour of small-and-medium-sized enterprises (SMEs) in the UK. Design/methodology/approach The authors first compare the actual and expected growth of family and non-family-owned SMEs. The authors then compare the growth behaviour of small family firms managed by owner-directors and small family businesses co-managed by family and non-family directors with the non-family-owned SMEs. Findings The authors find a negative effect of family ownership on actual and intended small business growth behaviours. In addition, the findings also suggest that small family firms co-managed by non-family and family directors are no different from non-family-owned firms, in terms of reporting past actual growth in employment size and turnover as well as expecting growth in workforce size and turnover. The authors also observe a significant difference in anticipating sales growth between family-controlled and non-family-controlled firms. However, this difference is not explained by the heterogeneity of a top management team. Practical implications The study has important implications for managerial practice to family firms and on policies that improve the growth of SMEs. Specifically, the competence of managers and decision makers matters considerably in evaluating the efficient operation of the business and maximising the economic growth in SMEs. Originality/value The study makes two important theoretical contributions to small business growth literature. First, the findings underline a negative family effect in the actual and expected growth behaviour of SMEs. Second, the mode of family ownership alone may not sufficiently capture family effect and offer a thorough understanding of growth behaviour in SMEs.