Tag Archives: Children

Worm Wars Continued

We have discussed results of deworming before and argued that it is important to treat at cluster level because of rapid re-infection from reservoirs in soil. A recent important meta-analysis compares deworming targeted at children versus a community-wide intervention.[1] It finds that community-wide approaches are more effective than treatment targeted at children for roundworms (Ascaris) and hookworms (Ancylostoma), but not whipworms (Trichuris). This finding is consistent with the much greater efficiency of the medicine in the former two worm types. The relative effect was greater in roundworms (odds ratio >16) than the more dangerous hookworms (OR >4), consistent with the shorter life-span of hookworm eggs than of roundworm eggs. These are important findings, but there is a worry that resistance may emerge with mass treatment. It would be interesting to see whether any studies have been done in slum populations specifically.

— Richard Lilford, CLAHRC WM Director

Reference:

  1. Clarke NE, Clements ACA, Doi SA, et al. Differential effect of mass deworming and targeted deworming for soil-transmitted helminth control in children: a systematic review and meta-analysis. Lancet. 2017; 389: 287-97.

Keeping a Child Back at School

We have often talked about Hattie’s work on evidence-based education.[1-4] Now we turn to retention (pages 97-99) – the act of keeping a child back and having them repeat a year of school on the grounds of poor performance.[5] Numerous papers, including a meta-analysis of 20 studies,[6] have shown retention to be associated with negative effects for the retained student. In subsequent years they have lower scores for a whole range of subjects: language, arts, reading, mathematics, work-study skills, and social studies, as well as social and emotional adjustment and behaviour, self-concept, and attitude to school. So a picture is starting to emerge – remember streaming is also unhelpful.[7] So any act that demeans a child or destroys her self-confidence is bad, while bright children are not held back by having less bright peers in the classroom. See also our News Blog on the Michelle Obama effect.[8]

— Richard Lilford, CLAHRC WM Director

References:

  1. Lilford RJ. Evidence-based Education. NIHR CLAHRC West Midlands News Blog. 24 February 2017.
  2. Lilford RJ. The School, the Teacher of the Pupil – Which is Most Important? NIHR CLAHRC West Midlands News Blog. 28 October 2016.
  3. Lilford RJ. Ask Not to Whether, But Why, Before the Bell Tolls. NIHR CLAHRC West Midlands News Blog. 29 July 2016.
  4. Lilford RJ. Education Update. NIHR CLAHRC West Midlands News Blog. 2 September 2016.
  5. Hattie J. Visible Learning: A Synthesis of Over 800 Meta-Analyses Relating to Achievement. Oxon, UK: Routledge, 2009.
  6. Jimerson SR. Meta-analysis of Grade Retention Research: Implications for Practice in the 21st Century. School Psychol Rev. 2001; 30(3): 420-37.
  7. Lilford RJ. Evidence-Based Education (or How Wrong the CLAHRC WM Director Was). NIHR CLAHRC West Midlands News Blog. 15 July 2016.
  8. Lilford RJ. More on Education. NIHR CLAHRC West Midlands News Blog. 16 September 2016.

More on Brain Health in Young Children and Effect on Life Course

Brain health in early childhood is a recurring theme of your News Blog. Peter Chilton referred me to an interesting article in Nature Human Behaviour published at the end of last year.[1] This study was based on a prospective study of children in the South Island of New Zealand. The investigators wanted to determine the prognosis for the 20% of the population with the worst brain health indicators at age three. These indicators include single parent family; low socioeconomic group; poor self-control; and low IQ. Outcome variables covered a range of important economically burdensome outcomes, such as obesity, cigarette smoking, and crime. These variables were harvested from various databases where health and crime statistics are recorded. A 20% ‘segment’ of this young population could be defined which predicted 80% of crime, and similar high rates on other outcomes. This 20:80 ratio, called the Pareto ratio, is often encountered in social science – for example, wealth distributes itself roughly in this proportion across many societies (about 20% of people control 80% of wealth). The authors say that their study shows plenty of ‘headroom’ for preventive interventions. That is to say, society could achieve massive gains if health and social outcomes among the highest risk segment could be improved to average levels. We have discussed interventions, such as early childhood education, before.[2-4] Many studies show statistically significant and economically worthwhile results for such interventions, but the gains come nowhere near the theoretical headroom defined here. Likely this is because brain health at age three is only partly the result of remediable factors.

— Richard Lilford, CLAHRC WM Director

References:

  1. Caspi A, Houts RM, Belsky DW, Harrington H, Hogan S, Ramrakha S, Poulton R, Moffitt TE. Childhood forecasting of a small segment of the population with large economic burden. Nature Hum Behav. 2016; 1: 0005.
  2. Lilford RJ. Pregnancy before age 16 – dropping quite rapidly from a peak in 1997. NIHR CLAHRC West Midlands News Blog. February 10, 2017.
  3. Lilford RJ. If you want to reduce partner violence or teenage pregnancy, then teach algebra and history? NIHR CLAHRC West Midlands News Blog. December 9, 2016.
  4. Lilford RJ. Evidence-based education (or how wrong the CLAHRC WM Director was). NIHR CLAHRC West Midlands News Blog. July 15, 2016.

Hidden Disadvantage to Caesarean Section

Some modern health care may end up changing the genetics of the human race. For example, the CLAHRC WM Director established a genetic basis for male infertility,[1] and sure enough, children born following injection of sperm into the mother’s egg have an increased risk of infertility.[2] What about Caesarean section? Childbirth is a struggle because, compared to all other animals (primates included), the baby’s head is big relative to the size of the mother’s pelvis. Evolution allows this to continue under an equilibrium where the distribution of pelvic sizes is maintained at a level where the beneficial effects of big brain/head balances the risk of catastrophic birth from a pelvis below the threshold where risk rises rapidly. Caesarean section skews natural selection and pelvic sizes according to this elegant mathematical model.[3] But are pelvic sizes indeed becoming smaller?

— Richard Lilford, CLAHRC WM Director

References:

  1. Lilford R, Jones AM, Bishop DT, Thornton J, Mueller R. Case-control study of whether subfertility in men is familial. BMJ. 1994; 309: 570.
  2. Belva F, Bonduelle M, Roelants M, et al. Semen quality of young adult ICSI offspring: the first results. Hum Reprod. 2016; 31(12): 2811-20.
  3. Mitteroecker P, Huttegger SM, Fischer B, Pavlicev M. Cliff-edge model of obstetric selection in humans. P Natl Acad Sci USA. 2016.

Early Introduction of Allergenic Foods for Breastfeeding Infants and Risk of Allergy

This is an important question for us all – is the early introduction of allergenic (allergy causing) foods, such as peanuts and egg, associated with higher risk of allergy? The short answer is no.[1] In fact the risk of clinical allergy is lower when peanut and egg is introduced early (at three months) than when introduced later (at six months). It was non-significantly lower by Intention-to-Treat, but significantly lower (p<0.003) in the per protocol analysis (2.4% vs. 7.3%). ‘Compliance’ was poor; less than half of cases in the early introduction group adhered to protocol. The non-adherers had similar rates of allergy to the control (normal practice/delayed introduction) group. There appeared to be a ‘dose’ response with higher intake of allergenic foods associated with greater reductions in the incidence of allergy. Biological testing for allergy gave even stronger protective results for early introduction than did the clinical data reported above. The results are consistent with previous observational and experimental studies. Taken in the round, the results are compelling, shifting probability densities sharply in favour of effectiveness. The World Health Organization recommends exclusive breast feeding to six months of age. Time for change in guidelines in high-income countries?

— Richard Lilford, CLAHRC WM Director

Reference:

  1. Perkin MR, Logan K, Tseng A, et al. Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants. New Engl J Med. 2016; 374: 1733-43.

Cluster Trial of Home Visits for Newborn Children in Sub-Saharan Africa

Forty percent of childhood deaths in low- and middle-income countries (LMICs) take place within the first month after birth. Trials conducted in Asia have shown that an intervention whereby home-visits are made over this crucial period of life is effective. Would it work in Africa? To find out, Betty Kirkwood and colleagues randomised 197 clusters in Ghana to intervention and control.[1] Mothers in the intervention clusters were to receive two home visits in pregnancy and three in the first week after birth. Coverage was good and the proportion of mothers who adopted health promoting behaviours increased. These behaviours included use of anti-mosquito bed-nets, timely transfer to a facility when appropriate, breastfeeding, ‘kangaroo’ care, delayed bathing of the baby, and hand-washing. Reductions in neonatal mortality observed in this trial alone were not significant, but a significant 12% reduction in mortality was estimated when the data were combined with those from the Asian trials in a meta-analysis. The CLAHRC WM Director could not find out whether the study was rural or urban. Trials of women’s groups [2] provide positive results in rural areas but not slums. It would be interesting to examine the effect of place of residence further since half of all African people will soon be urban, and more than half of those people will live in slums.

— Richard Lilford, CLAHRC WM Director

References:

  1. Kirkwood BR, Manu A, ten Asbroek AHA, et al. Effect of the Newhints home-visits intervention on neonatal mortality rate and care practices in Ghana: a cluster randomised controlled trial. Lancet. 2013; 381(9884): 2184-92.
  2. Prost A, Colbourn T, Seward N, et al. Women’s groups practising participatory learning and action to improve maternal and newborn health in resource-limited settings: systematic review and meta-analysis. Lancet. 2013; 381(9879): 1736-46.

 

Exposure of the Baby to a Rich Mixture of Coliform Organisms from the Birth Canal.

Previous research has pointed out that a good draught of such organisms seem to be healthy, as children brought up after delivery by Caesarean have a much higher incidence of atopic allergic reactions than those delivered through the birth canal.[1] Moreover, the colonic microbiome differs across babies born by vaginal vs. abdominal routes. Many have taken this evidence to heart, and have started to paint the baby’s face with a swab marinated in vaginal secretions. A balanced editorial in the BMJ [2] says that such a practice should not be recommended lest the baby be inoculated with less benign organisms called Beta Strep, resident in some vaginas. But if a woman wishes to practice such a procedure, she should not be inhibited from doing so, pending a trial big enough to determine the net long-term effects.

— Richard Lilford, CLAHRC WM Director

Reference:

  1. Neu J, & Rushing J. Cesarean versus Vaginal Delivery: Long term infant outcomes and the Hygiene Hypothesis. Clin Perinatol. 2011; 38(2): 321-31.
  2. Cunnington AJ, Sim K, Deierl A, et al. “Vaginal seeding” of infants born by caesarean section. BMJ. 2016; 352: i227.

 

More on Whole Genome / Whole Exon Germline Sequencing – This Time in Children Who Get Cancer

News Blog readers may remember a previous post on germline mutations in children with autism spectrum disorder (with and without congenital anomalies). Now germline mutations have been compared in children with cancer and controls.[1] Among 1,120 affected children, 8.5% had predisposing germline gene mutations. This was an underestimate because it included only genes that were identified in advance, on the grounds of established relevance to carcinogenesis. The real value may be 50% higher. Only 40% of patients with likely pathogenic mutations had any family history. The CLAHRC WM Director suspects that children with germline mutations are at risk of second primary cancers, and that some second primary cancers previously attributed to treatment of the primary cancer are in fact caused by germline mutations. The CLAHRC WM Director proposes a study to examine the incidence of such mutations in children with secondary cancers.

— Richard Lilford, CLAHRC WM Director

Reference:

  1. CZhang J, Walsh MF, Wu G, et al. Germline Mutations in Predisposition Genes in Pediatric Cancer. N Engl J Med. 2015; 373:2336-46.

The Obesity Challenge is Very Real, but What About Extreme Low Weight?

A body mass index under 16 in women is associated with anorexia in rich countries, but with malnutrition in low- and middle-income countries. It is associated with reduced life span, but the effects of energy supplementation in people who were seriously malnourished as children are uncertain. A recent cross-sectional study of over 40 countries using Demographic and Health Surveys shows a pooled incidence of extreme underweight of 1.8% (standardised for age). The prevalence is highest in India at over 6% and Bangladesh at over 3%.[1] Rates are declining quite rapidly in these countries, but overall at a very low rate and in some countries they are actually increasing.

— Richard Lilford, CLAHRC WM Director

Reference:

  1. Razak F, Corsi DJ, Slutsky AS, et al. Prevalence of Body Mass Index Lower Than 16 Among Women in Low- and Middle-Income Countries. JAMA. 2015; 314(20): 2164-71.

So Does Breastfeeding Increase Children’s IQ?

News Blog readers will have seen a short report on the Lancet article from Brazil associating breastfeeding with improved IQ.[1] Alas, probably not correct: at least any effect must be very small, according to a recent article that greatly improves on the Lancet paper.[2] First, the authors cite a thorough systematic review published in BMJ Open [3] and conclude that “Any observed associations are best explained by residual confounding.” Second, they conduct an observational analysis of nearly 12,000 children from the Twins Early Development Study. They find that breastfed girls, but not boys, have a significant, but very small, increase in IQ at age 2. They also find that the slope of the increase in IQ beyond age 2 is unaffected by whether or not the child was breastfed. They conclude that, while science cannot exclude tiny effects, the evidence for an effect of breastfeeding on IQ is very weak. Most studies show that the effect goes away or rapidly attenuates as adjustments are made for known confounders. These results are consistent with various experimental studies of nutritional supplements in early life, where null results contrast with positive results from social and educational interventions.

— Richard Lilford, CLAHRC WM Director

References:

  1. Victoria CG, et al. Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: a prospective birth cohort study from Brazil. Lancet Glob Health. 2015; 3(4): e199-205.
  2. von Stumm S & Plomin R. Breastfeeding and IQ Growth from Toddlerhood through Adolescence. PLoS One. 2015. [ePub].
  3. Walfisch A, Sermer C, Cressman A, Koren G. Breast milk and cognitive development – the role of confounders: a systematic review. BMJ Open 2013; 3: e003259.