SummaryBackgroundUnderweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults.MethodsWe pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5–19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5–19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity).FindingsRegional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (−0·01 kg/m2 per decade; 95% credible interval −0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69–1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64–1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (−0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50–1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4–1·2) in 1975 to 5·6% (4·8–6·5) in 2016 in girls, and from 0·9% (0·5–1·3) in 1975 to 7·8% (6·7–9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0–12·9) in 1975 to 8·4% (6·8–10·1) in 2016 in girls and from 14·8% (10·4–19·5) in 1975 to 12·4% (10·3–14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7–29·6) among girls and 30·7% (23·5–38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44–117) million girls and 117 (70–178) million boys wor...

This study was conducted in the context of a multicountry validation of indicators of diet quality and had the following objectives: 1) to determine how well dietary diversity scores (DDS) predict diet quality of children aged 6-23 mo in urban Madagascar; and 2) to assess whether the prediction was improved by changing the food groups included and by imposing a minimum amount restriction. Correlation and regression were used to describe the relationship between 4 diversity scores (2 based on 8 and 7 food groups, the latter excluding fats and oils, and 2 that imposed a 10-g minimum restriction on food groups) and the mean micronutrient density adequacy (MMDA) of the diet. MMDA, the dietary quality score used, was calculated as the mean individual micronutrient density adequacy for 9 or 10 "problem" nutrients (depending on age and breast-feeding status), each capped at 100%. We used sensitivity and specificity analysis to determine how well DDS predicted MMDA below or above selected cut-offs. All scores were positively correlated with MMDA. When the fats and oils group was omitted, correlations were 10-16% higher for breast-fed children and 19-28% higher for non-breast-fed children. Correlations were only slightly improved with the 10-g minimum. With the 7-food group score, a score of

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.DOI: http://dx.doi.org/10.7554/eLife.13410.001

Objectives: To develop scores for food variety and diversity to assess the overall dietary quality in an African rural area; and to study their relationship with the nutritional status of women of childbearing age. Design: Cross-sectional. Setting: Sahelian rural area in the North-East Burkina Faso (West Africa). Subjects: A total of 691 mothers with children below the age of 5 y, selected at random in 30 villages. Methods: A qualitative recall of women's food consumption during the previous 24 h made it possible to calculate a food variety score (FVS ¼ count of food items consumed) and a dietary diversity score (DDS ¼ count of food groups, among 14 groups). These scores were then divided into terciles. Body mass index (BMI), mid-upper arm circumference (MUAC) and body fat percentage (BFP) were used to determine the women's nutritional status. Results: The overall dietary quality was poor: mean FVS (s.d.) ¼ 8.3 (2.9) food items; mean DDS ¼ 5.1 (1.7) food groups. A clear relationship was shown between both FVS and DDS (in terciles) and most nutritional indices. Women with a FVS in the lowest tercile had a mean BMI of 20.1, while those in the highest tercile had a BMI of 20.9 (P ¼ 0.009). Those in the lowest tercile of DDS had a 22.8% prevalence of underweight vs 9.8% in the highest tercile (Po0.0001). The latter relationship remained significant even when the subjects' sociodemographic and economic characteristics were accounted for. Conclusion: Dietary scores measured at the individual level are good proxies for overall dietary quality of women living in a poor rural African area. These scores were also shown to be linked with the nutritional status of women. Financing: IRD financed the study with the assistance of UNICEF for the purchase of anthropometric equipment. The first author received a research allowance from the French Ministry of Research through the doctoral school 393 of Pierre and Marie Curie University (Paris VI).

In developing countries, dietary diversity is usually assessed during a single yearly period and the effects of seasonal variations remain unknown. We studied these variations in women living in a Sahelian rural area (Burkina Faso). A representative sample of 550 women was surveyed at the beginning and at the end of the seasonal cereal shortage in April and September 2003, respectively. For each season, a dietary diversity score (DDS) representing the number of food groups consumed over a 24-h period, was computed and nutritional status was assessed by the BMI. The DDS increased from 3.4 +/- 1.1 to 3.8 +/- 1.5 food groups between the beginning and the end of the shortage season (P < 0.0001), and the proportion of women exhibiting low DDS decreased from 31.6 to 8.1%. This was due to the consumption of foods available during the cereal shortage season and despite the decrease in the consumption of some purchased foods. The increase in DDS was lower in women for whom DDS was already high in April and vice versa. Over the same period, the percentage of underweight women (BMI <18.5 kg/m(2)) increased from 11.1 to 17.1%. The relation between DDS and the women's socioeconomic characteristics or nutritional status was weakened in September. Thus, in April, fewer women were underweight when their DDS was high than when it was medium or low [odds ratio = 0.3 (0.2; 0.6)], but not in September [odds ratio = 0.6 (0.3; 1.0)]. In such a context, it would be useful to measure dietary diversity at the beginning of the cereal shortage season, when many women exhibit low DDS.