Calcium Deficiency in Bangladesh: Burden and Proposed Solutions for the First 1000 Days

Abstract

Background: Bangladesh incurs among the highest prevalence of stunting and micronutrient deficiencies in the world, despite efforts against diarrheal disease, respiratory infections, and protein-energy malnutrition which have led to substantial and continuous reductions in child mortality over the past 35 years. Although programs have generally paid more attention to other micronutrients, the local importance of calcium to health has been less recognized.

Objective: To synthesize available information on calcium deficiency in Bangladesh in order to inform the design of an effective national calcium program.

Methods: We searched 3 online databases and a multitude of survey reports to conduct a narrative review of calcium epidemiology in Bangladesh, including population intake, determinants and consequences of deficiency, and tested interventions, with particular reference to young children and women of childbearing age. This was supplemented with secondary analysis of a national household survey in order to map the relative extent of calcium adequacy among different demographics.

Results: Intake of calcium is low in the general population of Bangladesh, with potentially serious and persistent effects on public health. These effects are especially pertinent to young children and reproductive-age women, by virtue of increased physiologic needs, disproportionately poor access to dietary calcium sources, and a confluence of other local determinants of calcium status in these groups.

Conclusion: A tablet supplementation program for pregnant women is an appealing approach for the reduction in preeclampsia and preterm birth. Further research is warranted to address the comparative benefit of different promising approaches in children for the prevention of rickets.

Keywords: Bangladesh; birthweight; calcium; child growth; maternal and child nutrition; pregnancy.

Figure 1. Potential intragenerational and intergenerational effects of severe calcium deficiency

In pregnancy, severe deficiency of calcium may threaten the mother (increasing the risk of preeclampsia,^, an important cause of maternal mortality in developing regions) and fetus (calcium deficiency may contribute to spontaneous preterm birth, and preeclampsia may contribute to loss of the fetus or medically induced preterm birth, the latter of which increases the risk of neonatal mortality). Preterm birth and intrauterine growth restriction (the latter of which may itself result from calcium deficiency in pregnancy) are both contributive to low birthweight, which is implicated in a variety of long-term physical and cognitive consequences, including stunted growth (which may be independently related to childhood calcium deficiency).^, Calcium-deficient children are at higher risk of nutritional rickets even in the absence of hypovitaminosis D, which may lead to pain, deformity, and fractures throughout life. Skeletal disease may be exacerbated as calcium deficiency persists into adolescence and adulthood, during which rickets is replaced with osteomalacia (for which experimental evidence implicates vitamin D as a probable additional requisite); even without vitamin D deficiency, calcium deficiency in adulthood may also contribute to a different pathology in osteopenia, which may progress to osteoporosis. Osteoporosis and osteomalacia predispose individuals to a spectrum of acute and chronic bone and musculoskeletal symptoms. The cycle repeats as various conditions - stunting, rickets, and osteomalacia - may contribute to cephalopelvic disproportion and obstructed labor. Calcium in breast milk appears to be relatively protected even in mothers consuming very little calcium.

Figure 2. Relative mean calcium adequacy (%) by sex, age group, and division (rural areas only)

Analysis is based on prior nutritional analysis by Sununtnasuk, Lividini, and Quabili (International Food Policy Research Institute) of the 2011 to 2012 Bangladesh Integrated Household Survey, representative of rural Bangladesh. The “relative mean adequacy” for each of the 70 subgroups is calculated as Mean (Intake_ij/EAR_ij * 100%) − 25.05%, where Intake_ij and EAR_ij denote the calcium intake (in mg) and EAR of individual j in subgroup i (this quotient is termed the individual’s “adequacy”), and 25.05% is the mean adequacy of the entire population of Bangladesh. EARs are drawn from WHO/FAO (2004). EAR indicates estimated average requirement; FAO, Food and Agriculture Organization; WHO, World Health Organization.