Focusing on linear growth and relative weight gain during early life – a winner ticket for human capital development and future adult health

We have seen in the previous blog that the children who are suffering from stunting (short stature) may look normal but the consequences of becoming and remaining stunted can be detrimental. In fact, we can observe an increased risk of morbidity and mortality, but also delays in cognitive (ability to think and understand) and physical development, which result in a decreased ability to learn and capacity to work.

In fact, stunted height (and not underweight) is a dreadful marker of multiple deprivations regarding food intake, care and play, clean water, good sanitation and health care. It is an important indicator of child well-being – not only physical growth but also cognitive and socio-emotional development.

These days, not only in the context of post Millennium Development Goals (MDGs) but also because of the importance to focus on sustainable human development, the key questions for nutritionists, pediatricians and policy makers are:

• What is the optimum age for promotion of growth for enhanced survival and human capital?
• Will this promotion necessarily lead to an increase in cardio-metabolic disease later in life?  

These aspects have their importance knowing that a lot of feeding programs in developing countries are aimed at older children, at a time where optimal linear growth is already compromise. For example, traditional school feeding programs that increase BMI with little effect on height might be doing more harm than good in terms of future health.

Why?

According to a study published in Lancet last month (see reference below), patterns already observed in the Western world are starting to be seen in low- and middle-income countries: i.e. putting on too much weight in relation to height in middle and late childhood (after 2 years old) can increase the risk for chronic diseases, such as diabetes, in later life.

This scientific analysis that involved five prospective birth cohort studies from Brazil, Guatemala, India, the Philippines, and South Africa showed that it is important to focus on improved nutrition in the first few years of life, i.e. the 1,000 days from the start of a woman’s pregnancy until her child’s 2nd birthday.

Their analysis showed that:

• Higher birth weight is associated with an adult BMI of greater than 25 kg/m² (mostly lean body mass – muscle, which is good), and a reduced likelihood of short stature and of not completing secondary school,
• Fast linear growth during the first 2 years of life is associated with increased adult height and amount of schooling,
• Weight gain earlier in infancy is not associated later with any increased risk of chronic disease. In fact, it is good for the child, good for survival, giving some protection from adult chronic disease and better educational attainment,
• Faster relative weight gain after the age of 2 years has little benefit for human capital, and weight gain after mid-childhood could lead to large adverse effects on later cardiovascular risk factors like elevated blood pressure. Notably, this is particularly true for weight gain that is not accompanied by height gain,
• In fact, rapid weight gain should not be promoted after the age of 2–3 years in children who are underweight (weight for age) but not wasted (weight for height)

This study shows the importance to promote nutrition and linear growth during the first 1,000 days of life (from conception to age 2 years), and also reinforces the importance of prevention of rapid relative weight gain after age 2 years.

These findings have implications for present practices in low-income and middle-income countries, particularly emphasizing the need to monitor linear growth as well as weight, and to avoid promotion of excess weight gain in children older than 2 years. Optimum growth patterns in early life are likely to lead to less undernutrition, increased human capital, and reduced risks of obesity and non-communicable diseases, thus addressing both components of the double burden of nutrition.

According to one of the authors, Dr Fall: “One of the challenges we are facing is the fact that we need to find ways to get very small children to be taller, and we don’t really know how to do it“. More work is needed on imaginative interventions to specifically promote height growth, instead of weight gain. These could include exclusive breast-feeding, long-chain polyunsaturated fatty acids like DHA, high-quality protein, and micronutrients.

Mortality and undernutrition are falling substantially in most parts of the world, except for Sub-Saharan Africa, and new targets are being formulated to replace the present set of 2015 MDGs. A new goal for optimum linear growth that is expressed as a reduction in stunting can replace the present target of a reduction in underweight alone, which is one of the indicators for the first MDGs towards the eradication of extreme poverty. This new target can be associated with the assessment of developmental functioning using a set of indicators based on the Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Development. This integrated approach will help to evaluate appropriately physical as well as cognitive and socio-emotional development, which is so important when building human capital.

 

References:

http://www.medscape.com/viewarticle/781535

Associations of linear growth and relative weight gain during early life with adult health and human capital in countries of low and middle income: findings from five birth cohort studies. Adair LS et al, Lancet 28^th March 2013 (http://download.thelancet.com/pdfs/journals/lancet/PIIS0140673613601038.pdf?id=a02f57d1811fcb77:524f7ce2:13db1412973:-60f11364479623359)