Summary Background Low birthweight (LBW) of less than 2500 g is an important marker of maternal and fetal health, predicting mortality, stunting, and adult-onset chronic conditions. Global nutrition targets set at the World Health Assembly in 2012 include an ambitious 30% reduction in LBW prevalence between 2012 and 2025. Estimates to track progress towards this target are lacking; with this analysis, we aim to assist in setting a baseline against which to assess progress towards the achievement of the World Health Assembly targets. Methods We sought to identify all available LBW input data for livebirths for the years 2000–16. We considered population-based national or nationally representative datasets for inclusion if they contained information on birthweight or LBW prevalence for livebirths. A new method for survey adjustment was developed and used. For 57 countries with higher quality time-series data, we smoothed country-reported trends in birthweight data by use of B-spline regression. For all other countries, we estimated LBW prevalence and trends by use of a restricted maximum likelihood approach with country-level random effects. Uncertainty ranges were obtained through bootstrapping. Results were summed at the regional and worldwide level. Findings We collated 1447 country-years of birthweight data (281 million births) for 148 countries of 195 UN member states (47 countries had no data meeting inclusion criteria). The estimated worldwide LBW prevalence in 2015 was 14·6% (uncertainty range [UR] 12·4–17·1) compared with 17·5% (14·1–21·3) in 2000 (average annual reduction rate [AARR] 1·23%). In 2015, an estimated 20·5 million (UR 17·4–24·0 million) livebirths were LBW, 91% from low-and-middle income countries, mainly southern Asia (48%) and sub-Saharan Africa (24%). Interpretation Although these estimates suggest some progress in reducing LBW between 2000 and 2015, achieving the 2·74% AARR required between 2012 and 2025 to meet the global nutrition target will require more than doubling progress, involving both improved measurement and programme investments to address the causes of LBW throughout the lifecycle. Funding Bill & Melinda Gates Foundation, The Children's Investment Fund Foundation, United Nations Children's Fund (UNICEF), and WHO.

Age-appropriate complementary feeding practices are far from optimal among low-and middleincome countries with available data. The evidence on the association between feeding practices and linear growth is mixed. We sought to systematically examine the association between two indictors of dietary quality-dietary diversity and animal source food (ASF) consumption (WHO, 2008)-and stunting (length-for-age z-score) employing existing data from 39 Demographic and Health Surveys. Data on 74,548 children aged 6-23 months were pooled and multiple logistic regression models, adjusting for child, maternal, and household characteristics, employed to assess the association between dietary quality and stunting. Stratified models by child age and by World Bank country-income classifications (World Bank, 2015) were also applied. Children aged 6-23 months consuming zero food groups in the previous day had a 1.345 higher odds of being stunted when compared to the reference group (≥5 food groups); those who did not consume any ASF in the previous day had a 1.436 higher odds of being stunted compared to children consuming all three types of ASF (egg, meat, and dairy). We estimated that 2,629 cases of stunting would have been averted (12.6% of those stunted) among the population studied if all children had consumed five or more food groups. Outcomes by country-income groupings showed larger associations of diet diversity and ASF consumption for upper-and lower-middle income countries compared to low-income countries. In summary, dietary diversity and ASF consumption were associated with stunting, with associations varying by stratified groups.KEYWORDS animal source foods, child growth, diet diversity, infant and young child feeding, stunting, WHO feeding indicators

These findings provide encouraging evidence that a package of multisector interventions has the potential to produce reductions in childhood stunting.

Background The Global Nutrition Target of reducing low birthweight (LBW) by at least 30% between 2012 and 2025 has led to renewed interest in producing accurate, population-based, national low birthweight (LBW) estimates. Low- and middle-income countries rely on household surveys for birthweight data. These data are frequently incomplete and exhibit strong “heaping”. Standard survey adjustment methods produce estimates with residual bias. The global database used to report against the LBW Global Nutrition Target adjusts survey data using a new MINORMIX approach: 1) multiple imputation to address missing birthweights, followed by 2) use of a two-component normal mixture model to account for heaping of birthweights. Objective We evaluated the performance of the MINORMIX birthweight adjustment approach and alternative methods against gold-standard measured birthweights in rural Nepal. Design As part of a community-randomized trial in rural Nepal, we measured “gold-standard” birthweights at birth and returned 1–24 months later to collect maternally reported birthweights using standard survey methods. We compared estimates of LBW from maternally reported data derived using: 1) the new MINORMAX approach; 2) the previously used Blanc-Wardlaw adjustment; 3) no adjustment for missingness or heaping against our gold-standard. We also assessed the independent contribution of multiple imputation and curve fitting to LBW adjustment. Results Our gold-standard found 27.7% of newborns were LBW. The unadjusted LBW estimate based on maternal report with simulated missing birthweights was 14.5% (95%CI: 11.6–18.0%). Application of the Blanc-Wardlaw adjustment increased the LBW estimate to 20.6%. The MINORMIX approach produced an estimate of 26.4% (95%CI: 23.5–29.3%) LBW, closest to and with bounds encompassing the measured point estimate. Conclusions In a rural Nepal validation dataset, the MINORMIX method generated a more accurate LBW estimate than the previously applied adjustment method. This supports the use of the MINORMIX method to produce estimates for tracking the LBW Global Nutrition Target. Clinical Trial Registry: NCT01177111 at https://clinicaltrials.gov/ct2/show/NCT01177111.

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