artbin: Extended sample size for randomized trials with binary outcomes.

We describe the command artbin, which offers various new facilities for the calculation of sample size for binary outcome variables that are not otherwise available in Stata. While artbin has been available since 2004, it has not been previously described in the Stata Journal. artbin has been recently updated to include new options for different statistical tests, methods and study designs, improved syntax, and better handling of noninferiority trials. In this article, we describe the updated version of artbin and detail the various formulas used within artbin in different settings.

artcat: Sample-size calculation for an ordered categorical outcome.

We describe a new command, artcat, that calculates sample size or power for a randomized controlled trial or similar experiment with an ordered categorical outcome, where analysis is by the proportional-odds model. artcat implements the method of Whitehead (1993, Statistics in Medicine 12: 2257-2271). We also propose and implement a new method that 1) allows the user to specify a treatment effect that does not obey the proportional-odds assumption, 2) offers greater accuracy for large treatment effects, and 3) allows for noninferiority trials. We illustrate the command and explore the value of an ordered categorical outcome over a binary outcome in various settings. We show by simulation that the methods perform well and that the new method is more accurate than Whitehead's method.

Effect of a micronutrient-rich snack taken preconceptionally and throughout pregnancy on ultrasound measures of fetal growth: The Mumbai Maternal Nutrition Project (MMNP).

Improving micronutrient intakes of under-nourished mothers in low- and middle-income countries increases birth weight, but there is little data on the nature and timing during gestation of any effects on fetal growth. Ultrasound measures of fetal size were used to determine whether and when a food-based supplement affected fetal growth. Non-pregnant women living in Mumbai slums, India (N = 6,513), were randomly assigned to receive either a daily micronutrient-rich snack containing green leafy vegetables, fruit, and milk (treatment) or a snack made from lower-micronutrient vegetables (control) in addition to their usual diet from before pregnancy until delivery. From 2,291 pregnancies, the analysis sample comprised 1,677 fetuses (1,335 fetuses of women supplemented for ≥3 months before conception). First-trimester (median: 10 weeks, interquartile range: 9-12 weeks) fetal crown-rump length was measured. Fetal head circumference, biparietal diameter, femur length, and abdominal circumference were measured during the second (19, 19-20 weeks) and third trimesters (29, 28-30 weeks). The intervention had no effect on fetal size or growth at any stage of pregnancy. In the second trimester, there were interactions between parity and allocation group for biparietal diameter (p = .02) and femur length (p = .04) with both being smaller among fetuses of primiparous women and larger among those of multiparous women, in the treatment group compared with the controls. Overall, a micronutrient-rich supplement did not increase standard ultrasound measures of fetal size and growth at any stage of pregnancy. Additional ultrasound measures of fetal soft tissues (fat and muscle) may be informative.

A Daily Snack Containing Leafy Green Vegetables, Fruit, and Milk before and during Pregnancy Prevents Gestational Diabetes in a Randomized, Controlled Trial in Mumbai, India.

BACKGROUND: Prospective observational studies suggest that maternal diets rich in leafy green vegetables and fruit may help prevent gestational diabetes mellitus (GDM). OBJECTIVE: Our objective was to test whether increasing women's dietary intake of leafy green vegetables, fruit, and milk before conception and throughout pregnancy reduced their risk of GDM. METHODS: Project SARAS ("excellent") (2006-2012) was a nonblinded, individually randomized, controlled trial in women living in slums in the city of Mumbai, India. The interventions included a daily snack made from leafy green vegetables, fruit, and milk for the treatment group or low-micronutrient vegetables (e.g., potato and onion) for the control group, in addition to the usual diet. Results for the primary outcome, birth weight, have been reported. Women were invited to take an oral-glucose-tolerance test (OGTT) at 28-32 wk gestation to screen for GDM (WHO 1999 criteria). The prevalence of GDM was compared between the intervention and control groups, and Kernel density analysis was used to compare distributions of 120-min plasma glucose concentrations between groups. RESULTS: Of 6513 women randomly assigned, 2291 became pregnant; of these, 2028 reached a gestation of 28 wk, 1008 (50%) attended for an OGTT, and 100 (9.9%) had GDM. In an intention-to-treat analysis, the prevalence of GDM was reduced in the treatment group (7.3% compared with 12.4% in controls; OR: 0.56; 95% CI: 0.36, 0.86; P = 0.008). The reduction in GDM remained significant after adjusting for prepregnancy adiposity and fat or weight gain during pregnancy. Kernel density analysis showed that this was explained by the fact that fewer women in the treatment group had a 2-h glucose concentration in the range 7.5-10.0 mmol/L. CONCLUSIONS: In low-income settings, in which women have a low intake of micronutrient-rich foods, improving dietary micronutrient quality by increasing intake of leafy green vegetables, fruit, and/or milk may have an important protective effect against the development of GDM. This trial was registered at www.controlled-trials.com as ISRCTN62811278.

Contribution of food sources to the vitamin B12 status of South Indian children from a birth cohort recruited in the city of Mysore.

OBJECTIVE: There is evidence that subclinical vitamin B12 (B12) deficiency is common in India. Vegetarianism is prevalent and therefore meat consumption is low. Our objective was to explore the contribution of B12-source foods and maternal B12 status during pregnancy to plasma B12 concentrations. DESIGN: Maternal plasma B12 concentrations were measured during pregnancy. Children's dietary intakes and plasma B12 concentrations were measured at age 9.5 years; B12 and total energy intakes were calculated using food composition databases. We used linear regression to examine associations between maternal B12 status and children's intakes of B12 and B12-source foods, and children's plasma B12 concentrations. SETTING: South Indian city of Mysore and surrounding rural areas. SUBJECTS: Children from the Mysore Parthenon Birth Cohort (n 512, 47.1 % male). RESULTS: Three per cent of children were B12 deficient (<150 pmol/l). A further 14 % had 'marginal' B12 concentrations (150-221 pmol/l). Children's total daily B12 intake and consumption frequencies of meat and fish, and micronutrient-enriched beverages were positively associated with plasma B12 concentrations (P=0.006, P=0.01 and P=0.04, respectively, adjusted for socio-economic indicators and maternal B12 status). Maternal pregnancy plasma B12 was associated with children's plasma B12 concentrations, independent of current B12 intakes (P<0.001). Milk and curd (yoghurt) intakes were unrelated to B12 status. CONCLUSIONS: Meat and fish are important B12 sources in this population. Micronutrient-enriched beverages appear to be important sources in our cohort, but their high sugar content necessitates care in their recommendation. Improving maternal B12 status in pregnancy may improve Indian children's status.

The Association of Maternal Age With Fetal Growth and Newborn Measures: The Mumbai Maternal Nutrition Project (MMNP).

BACKGROUND: Young maternal age is associated with poorer birth outcomes, but the mechanisms are incompletely understood. Using data from a prospective cohort of pregnant women living in Mumbai slums, India, we tested whether lower maternal age was associated with adverse fetal growth. METHODS: Fetal crown-rump length (CRL) was recorded at a median (interquartile range, IQR) of 10 weeks' gestation (9-10 weeks). Head circumference (HC), biparietal diameter (BPD), femur length (FL), and abdominal circumference (AC) were recorded at 19 (19-20) and 29 (28-30) weeks. Newborns were measured at a median (IQR) of 2 days (1-3 days) from delivery. Gestation was assessed using prospectively collected menstrual period dates. RESULTS: The sample comprised 1653 singleton fetuses without major congenital abnormalities, of whom 1360 had newborn measurements. Fetuses of younger mothers had smaller CRL (0.01 standard deviation [SD] per year of maternal age; 95% confidence interval CI: 0.00-0.02 1 ; P = .04), and smaller HC, FL, and AC at subsequent visits. Fetal growth of HC (0.04 cm; 95% CI: 0.02-0.05; P < .001), BPD (0.01 cm; 95% CI: 0.00-0.01; P = .009), FL (0.04 cm; 95% CI: 0.02-0.06; P < .001), and AC (0.01 cm; 95% CI: 0.00-0.01; P = .003) up to the third trimester increased with maternal age. Skinfolds, head, and mid-upper arm circumferences were smaller in newborns of younger mothers. Adjusting for maternal prepregnancy socioeconomic status, body mass index, height, and parity attenuated the associations between maternal age and newborn size but did not change those with fetal biometry. CONCLUSION: Fetuses of younger mothers were smaller from the first trimester onward and grew slower, independently of known confounding factors.

Dietary micronutrient intakes among women of reproductive age in Mumbai slums.

OBJECTIVES: To (1) describe micronutrient intakes among women of reproductive age living in Mumbai slums; (2) assess the adequacy of these intakes compared with reference values; (3) identify important dietary sources of micronutrients. SUBJECTS/METHODS: Participants were 6426 non-pregnant women aged 16-39 years, registered in a randomised controlled trial of a food-based intervention set in the Bandra, Khar and Andheri areas of Mumbai, India. Cross-sectional quantified food frequency questionnaire (FFQ) data were collected. Vitamin (n = 9) and mineral (n = 6) intakes were calculated and analysed in relation to dietary reference values (DRVs). Important dietary sources were identified for each micronutrient. RESULTS: Median intakes of all micronutrients, except vitamin E, were below the FAO/WHO reference nutrient intake (RNI). Intakes of calcium, iron, vitamin A and folate were furthest from the RNI. For seven of the micronutrients, over half of the women had intakes below the lower reference nutrient intake (LRNI); this figure was over 75% for calcium and riboflavin. The majority of women (93%) had intakes below the EAR for 5 or more micronutrients, and 64% for 10 or more. Adolescents had lower intakes than women aged >19 years. Less than 1% of adult women and no adolescents met the EAR for all micronutrients. Animal source foods and micronutrient-rich fruit and vegetables were consumed infrequently. CONCLUSIONS: These women had low intakes of multiple micronutrients, increasing their risk of insufficiency. There is a need to determine the factors causing poor intakes, to direct interventions that improve diet quality and nutritional sufficiency.

Effectiveness of a 5-year school-based intervention programme to reduce adiposity and improve fitness and lifestyle in Indian children; the SYM-KEM study.

DESIGN: Non-randomised non-blinded school-based intervention study. SETTING: Two schools in the cities of Pune and Nasik, India. PARTICIPANTS: The intervention group comprised children attending a Pune school from 7-10 years until 12-15 years of age. Two control groups comprised children of the same age attending a similar school in Nasik, and children in the Pune intervention school but aged 12-15 years at the start of the study. INTERVENTION: A 5-year multi-intervention programme, covering three domains: physical activity, diet and general health, and including increased extracurricular and intracurricular physical activity sessions; daily yoga-based breathing exercises; making physical activity a 'scoring' subject; nutrition education; healthier school meals; removal of fast-food hawkers from the school environs; and health and nutrition education for teachers, pupils and families. MAIN OUTCOME MEASURES: Body mass index (BMI), waist circumference, physical fitness according to simple tests of strength, flexibility and endurance; diet; and lifestyle indicators (time watching TV, studying and actively playing). RESULTS: After 5 years the intervention children were fitter than controls in running, long jump, sit-up and push-up tests (p<0.05 for all). They reported spending less time sedentary (watching TV and studying), more time actively playing and eating fruit more often (p<0.05). The intervention did not reduce BMI or the prevalence of overweight/obesity, but waist circumference was lower than in the Pune controls (p=0.004). CONCLUSIONS: It was possible to achieve multiple health-promoting changes in an academically competitive Indian school. These changes resulted in improved physical fitness, but had no impact on the children's BMI or on the prevalence of overweight/obesity.

Improving women's diet quality preconceptionally and during gestation: effects on birth weight and prevalence of low birth weight--a randomized controlled efficacy trial in India (Mumbai Maternal Nutrition Project).

BACKGROUND: Low birth weight (LBW) is an important public health problem in undernourished populations. OBJECTIVE: We tested whether improving women's dietary micronutrient quality before conception and throughout pregnancy increases birth weight in a high-risk Indian population. DESIGN: The study was a nonblinded, individually randomized controlled trial. The intervention was a daily snack made from green leafy vegetables, fruit, and milk (treatment group) or low-micronutrient vegetables (potato and onion) (control group) from ≥ 90 d before pregnancy until delivery in addition to the usual diet. Treatment snacks contained 0.69 MJ of energy (controls: 0.37 MJ) and 10-23% of WHO Reference Nutrient Intakes of ß-carotene, riboflavin, folate, vitamin B-12, calcium, and iron (controls: 0-7%). The primary outcome was birth weight. RESULTS: Of 6513 women randomly assigned, 2291 women became pregnant, 1962 women delivered live singleton newborns, and 1360 newborns were measured. In an intention-to-treat analysis, there was no overall increase in birth weight in the treatment group (+26 g; 95% CI: -15, 68 g; P = 0.22). There was an interaction (P < 0.001) between the allocation group and maternal prepregnant body mass index (BMI; in kg/m(2)) [birth-weight effect: -23, +34, and +96 g in lowest (<18.6), middle (18.6-21.8), and highest (>21.8) thirds of BMI, respectively]. In 1094 newborns whose mothers started supplementation ≥ 90 d before pregnancy (per-protocol analysis), birth weight was higher in the treatment group (+48 g; 95% CI: 1, 96 g; P = 0.046). Again, the effect increased with maternal BMI (-8, +79, and +113 g; P-interaction = 0.001). There were similar results for LBW (intention-to-treat OR: 0.83; 95% CI: 0.66, 1.05; P = 0.10; per-protocol OR = 0.76; 95% CI: 0.59, 0.98; P = 0.03) but no effect on gestational age in either analysis. CONCLUSIONS: A daily snack providing additional green leafy vegetables, fruit, and milk before conception and throughout pregnancy had no overall effect on birth weight. Per-protocol and subgroup analyses indicated a possible increase in birth weight if the mother was supplemented ≥ 3 mo before conception and was not underweight. This trial was registered at www.controlled-trials.com/isrctn/ as ISRCTN62811278.