Much is known about national trends in child undernutrition, but there is little information on how socio-economic inequalities are evolving over time. We aimed to assess socio-economic inequalities in stunting prevalence over time.

We selected nationally representative surveys carried out since the mid-1990s for which information was available on asset indices and on child anthropometry. We identified twenty-five countries that had at least two surveys over an interval of 10 years or more, totalling eighty-seven surveys. Stunting prevalence was calculated according to wealth quintiles. Absolute and relative inequalities were calculated and time trends were obtained by regression.

Nationally representative household surveys from twenty-five low- and middle-income countries.

Children <5 years of age.

National prevalence declined significantly in twenty-two of the twenty-five countries. In eighteen out of twenty-five countries, relative reductions were higher among the rich than among the poor. Overall, there was no indication that inequalities improved. Striking examples are Nepal, with a 17·0 percentage points decline in stunting per decade, but where inequalities increased sharply; and Brazil, where stunting fell by 6·7 percentage points and inequalities were all but eliminated.

Global progress in reducing stunting has not been accompanied by improved equity, but countries varied markedly in how successful they were in reducing prevalence among the poorest children. It is important to document how some countries were able to reduce inequalities, so that these lessons can be used to foster global progress, particularly in light of the increased importance of within-country inequalities in the post-2015 agenda.

To identify a body fat percentage (%BF) threshold related to an adverse cardiometabolic profile and its surrogate BMI cut-off point.

Cross-sectional study.

Two public schools in poor urban areas on the outskirts of Guatemala City.

A convenience sample of ninety-three healthy, prepubertal, Ladino children (aged 7–12 years).

Spearman correlations of cardiometabolic parameters were higher with %BF than with BMI-for-age Z-score. BMI-for-age Z-score and %BF were highly correlated (r=0·84). The %BF threshold that maximized sensitivity and specificity for predicting an adverse cardiometabolic profile (elevated homeostasis model assessment–insulin resistance index and/or total cholesterol:HDL-cholesterol ratio) according to receiver operating characteristic curve analysis was 36 %. The BMI-for-age Z-score cut-off point that maximized the prediction of BF ≥ 36 % by the same procedure was 1·5. The area under the curve (AUC) for %BF and for BMI data showed excellent accuracy to predict an adverse cardiometabolic profile (AUC 0·93 (sd 0·04)) and excess adiposity (AUC 0·95 (sd 0·02)).

Since BMI standards have limitations in screening for adiposity, specific cut-off points based on ethnic-/sex- and age-specific %BF thresholds are needed to better predict an adverse cardiometabolic profile.

To evaluate the impact of the Baby-Friendly Hospital Initiative (BFHI) on breast-feeding initiation and duration overall and according to maternal education.

Quasi-experimental study using data from five states (Alaska, Maine, Nebraska, Ohio, Washington) that participated in the Pregnancy Risk Assessment Monitoring System from 1999 to 2009. Using differences-in-differences models that included year and hospital fixed effects, we compared rates of breast-feeding initiation and duration (any and exclusive breast-feeding for ≥4 weeks) before and after BFHI accreditation between mothers who gave birth in hospitals that were accredited or became accredited and mothers from matched non-BFHI facilities. We stratified analyses into lower and higher education groups.

Thirteen BFHI hospitals and nineteen matched non-BFHI facilities across five states in the USA.

Mothers (n 11 723) who gave birth in BFHI hospitals and mothers (n 13 604) from nineteen matched non-BFHI facilities.

Although we did not find overall differences in breast-feeding initiation between birth facilities that received BFHI accreditation compared with non-Baby-Friendly facilities (adjusted coefficient = 0·024; 95 % CI −0·00, 0·51), breast-feeding initiation increased by 3·8 percentage points among mothers with lower education who delivered in Baby-Friendly facilities (P = 0·05), but not among mothers with higher education (adjusted coefficient = 0·002; 95 % CI −0·04, 0·05). BFHI accreditation also increased exclusive breast-feeding for ≥4 weeks by 4·5 percentage points (P = 0·02) among mothers with lower education who delivered in BFHI facilities.

By increasing breast-feeding initiation and duration among mothers with lower education, the BFHI may reduce socio-economic disparities in breast-feeding.

To examine changes in the food choices of New Zealand (NZ) adults, between the 1997 National Nutrition Survey (NNS97) and the 2008/09 NZ Adult Nutrition Survey (2008/09 NZANS).

The 2008/09 NZANS and the NNS97 were cross-sectional surveys of NZ adults (aged 15 years and over). Dietary intake data were collected using a computer-based 24 h diet recall. Logistic regression models were used to examine changes over time in the percentage reporting each food group, with survey year, sex and age group (19–30 years, 31–50 years, 51–70 years, ≥71 years) as the variables.

NZ households.

Adults aged 19 years and over (NNS97, n 4339; 2008/09 NZANS, n 3995).

In the 2008/09 NZANS compared with NNS97, males and females were less likely to report consuming bread, potatoes, beef, vegetables, breakfast cereal, milk, cheese, butter, pies, biscuits, cakes and puddings, and sugar/confectionery (all P<0·001). In contrast, there was an increase in the percentage reporting rice and rice dishes (P<0·001), and among females a reported increase in snacks and snack bars (e.g. crisps, extruded snacks, muesli bars; P=0·007) and pasta and pasta dishes (P=0·017). Although food choices were associated with sex and age group, there were few differential changes between the surveys by sex or age group.

For all age groups there was a shift in the percentage who reported consuming the traditional NZ foods, namely bread, beef, potatoes and vegetables, towards more rice and rice dishes. Declines in the consumption of butter, pies, biscuits, cakes and puddings are congruent with current dietary guidelines.

Elderly people may be at particular risk of Zn deficiency due to an increased prevalence of malnutrition. The aim of the present study was to evaluate the Zn status in community-living elderly people at risk of malnutrition.

Cross-sectional population-based survey. Individuals at risk of malnutrition were identified by the Malnutrition Universal Screening Tool. Zn status was assessed by measuring serum Zn. Logistic regression was performed to evaluate the association between the risk of malnutrition and Zn deficiency.

Municipality of Tromsø, Norway.

Random sample of 743 men and 778 women aged 65–87 years.

Zn deficiency was found in 10·1 % of the participants, including 13·1 % of the men and 7·3 % of the women. Among the men and women at risk of malnutrition, 31·0 % and 12·7 %, respectively, had Zn deficiency. In a model adjusted for age, gender, serum albumin and smoking status, Zn deficiency was positively associated with the risk of malnutrition (OR=2·2; 95 % CI 1·3, 3·6).

Overall, Zn deficiency was found in one out of ten community-living elderly people and was associated with the risk of malnutrition. Our results encourage the assessment of Zn status in elderly people at risk of malnutrition, with a special emphasis on elderly men.

Black and Hispanic individuals synthesize less vitamin D per unit of sun exposure than white individuals. The relationship between UV radiation and vitamin D insufficiency in minorities has not been well explored.

Prospective cohort study.

Using the National Health and Nutrition Examination Survey, we obtained serum vitamin D levels for non-Hispanic Whites, Hispanics and non-Hispanic Blacks aged ≥18 years from 2000–2006. We linked these data with the average monthly solar UV index by census tract and data on sun exposure, vitamin D supplementation, health and demographics. We used multivariable regression analyses to assess vitamin D deficiency (<15 ng/ml) and insufficiency (<20 ng/ml) in January (when the UV index was lowest) by race/ethnicity and geography.

Adults (n 14 319) aged ≥18 years.

A 1-point increase in the UV index was associated with a 0·51 ng/ml increase in vitamin D (95 % CI 0·35, 0·67 ng/ml; P<0·001). Non-Hispanic Black race and Hispanic ethnicity were associated with a 7·47 and 3·41 ng/ml decrease in vitamin D, respectively (both P<0·001). In January, an estimated 65·4 % of non-Hispanic Blacks were deficient in vitamin D, compared with 28·9 % of Hispanics and 14·0 % of non-Hispanic Whites. An estimated 84·2 % of non-Hispanic Blacks were insufficient in vitamin D v. 56·3 % of Hispanics and 34·8 % of non-Hispanic Whites. More non-Hispanic Blacks were estimated to be deficient in vitamin D in January in the highest UV index quartile than were non-Hispanic Whites in the lowest UV index quartile (60·2 % v. 25·7 %).

Wintertime vitamin D insufficiency is pervasive among minority populations, and not uncommon among non-Hispanic Whites.

To assess the iodine status of Swiss population groups and to evaluate the influence of iodized salt as a vector for iodine fortification.

The relationship between 24 h urinary iodine and Na excretions was assessed in the general population after correcting for confounders. Single-day intakes were estimated assuming that 92 % of dietary iodine was excreted in 24 h urine. Usual intake distributions were derived for male and female population groups after adjustment for within-subject variability. The estimated average requirement (EAR) cut-point method was applied as guidance to assess the inadequacy of the iodine supply.

Public health strategies to reduce the dietary salt intake in the general population may affect its iodine supply.

The study population (1481 volunteers, aged ≥15 years) was randomly selected from three different linguistic regions of Switzerland.

The 24 h urine samples from 1420 participants were determined to be properly collected. Mean iodine intakes obtained for men (n 705) and women (n 715) were 179 (sd 68·1) µg/d and 138 (sd 57·8) µg/d, respectively. Urinary Na and Ca, and BMI were significantly and positively associated with higher iodine intake, as were men and non-smokers. Fifty-four per cent of the total iodine intake originated from iodized salt. The prevalence of inadequate iodine intake as estimated by the EAR cut-point method was 2 % for men and 14 % for women.

The estimated prevalence of inadequate iodine intake was within the optimal target range of 2–3 % for men, but not for women.

The present study determined trends in malnutrition among under-5 children in urban and rural areas of Bangladesh.

Surveillance.

The study was conducted in the urban Dhaka and the rural Matlab hospitals of the International Centre for Diarrhoeal Disease Research, Bangladesh, where every fiftieth patient and all patients coming from the Health and Demographic Surveillance System were enrolled.

A total of 28 816 under-5 children were enrolled at Dhaka from 1993 to 2012 and 11 533 at Matlab between 2000 and 2012.

In Dhaka, 46 % of the children were underweight, 39 % were stunted and 28 % were wasted. In Matlab, the corresponding figures were 39 %, 31 % and 26 %, respectively. At Dhaka, 0·5 % of the children were overweight and obese when assessed by weight-for-age Z-score >+2·00, 1·4 % by BMI-for-age Z-score >+2·00 and 1·4 % by weight-for-height Z-score >+2·00; in Matlab the corresponding figures were 0·5 %, 1·4 % and 1·4 %, respectively. In Dhaka, the proportion of underweight, stunting and wasting decreased from 59 % to 28 % (a 53 % reduction), from 54 % to 22 % (59 % reduction) and from 33 % to 21 % (36 % reduction), respectively, between 1993 and 2012. In Matlab, these indicators decreased from 51 % to 27 % (a 47 % reduction), from 36 % to 25 % (31 % reduction) and from 34 % to 14 % (59 % reduction), respectively, from 2000 to 2012. On the other hand, the proportion of overweight (as assessed by BMI-for-age Z-score) increased significantly over the study period in both Dhaka (from 0·6 % to 2·6 %) and Matlab (from 0·8 % to 2·2 %).

The proportion of malnourished under-5 children has decreased gradually in both urban and rural Bangladesh; however, the reduction rates are not in line with meeting Millennium Development Goal 1. Trends for increasing childhood obesity have been noted during the study period as well.

To examine associations between students’ socio-economic status (SES) and school-day dietary intake, and the roles of parents and peers in shaping these associations.

A cross-sectional survey measured school-day intake of vegetables, whole grains, low-fat milk, packaged snack foods and sugar-sweetened beverages. Logistic regression models examined associations between SES (parental education and food insecurity status) and dietary outcomes during or en route to or from school, and examined whether peer modelling or parental norms potentially mediated the associations between SES and dietary outcomes.

Twenty-six public schools in Vancouver, Canada in 2012.

Nine hundred and fifty students in grades 5–8.

Students whose parents completed some college, compared with those completing high school or less, were significantly more likely to consume vegetables daily (unadjusted OR=1·85; 95 % CI 1·06, 3·22) and students whose parents completed college or university were significantly less likely to consume sugar-sweetened beverages daily (unadjusted OR=0·67; 95 % CI 0·47, 0·94). Food secure students were also significantly less likely to consume sugar-sweetened beverages daily compared with food insecure students (unadjusted OR=0·52; 95 % CI 0·29, 0·92). Parental norms, but not peer modelling, emerged as a potential mediator of the association between SES and vegetable intake. SES was not significantly associated with the remaining dietary outcomes.

Higher SES was significantly associated with two of five school-day dietary outcomes and predicted higher likelihood of daily nutritious food choices at school. The present study suggests that there is room for improvement in school-day dietary quality for students from all SES backgrounds in Vancouver.