Age at childbirth and change in BMI across the life-course: evidence from the INCAP Longitudinal Study

Background: Parity has been associated with both short- and long-term weight gain in women. However, it is not clear if timing of parity across the reproductive age has different associations with BMI. Methods: To prospectively assess the association between age at childbirth and maternal change in BMI, we analyzed data from the ongoing INCAP Longitudinal Study, which started in 1969 in four villages in Guatemala. Cohort women (n=778) provided information on reproductive history and anthropometric measures were measured in 1988-89 (adolescence, 15 to 25y), 2002-04 (early adulthood, 26 to 36y) and 2015-17 (mid adulthood, 37 to 55y). We evaluated the associations of number of live births in the period preceding each study wave (1969-77 to 1988-89, 1988-89 to 2002-04 and 2002-04 to 2015-17) with BMI change in the same period using multivariable linear regression models. Results: Number of live births between 1988 and 89 and 2002-04 was positively associated with increased BMI, while there was not an association between number of live births and BMI in the other intervals. Women who had one, two, or three or more children between 1988 and 89 and 2002-04 had 0.90 (kg/m2, 95% CI: -0.55, 2.35), 2.39 (kg/m2, 95% CI: 1.09, 3.70) and 2.54 (kg/m2, 95% CI: 1.26, 3.82) higher BMI, respectively, than women who did not give birth in the same period. Conclusions: Our findings suggest that women who had three or more children during early adulthood gained more weight compared to women who had no children in the same period. In contrast, women who had children earlier or later in their reproductive lives did not gain additional weight compared to those who did not have children during that period. Childbirth may have different

Effect of omega-3 fatty acids supplementation during pregnancy on lung function in preschoolers: a clinical trial.

RATIONALE: Prenatal omega-3 fatty acids improve alveolarization, diminish inflammation, and improve pulmonary growth, but it is unclear whether these outcomes translate into improved postnatal lung function. OBJECTIVE: We assessed the effect of prenatal supplementation with docosahexaenoic acid (DHA) on offspring lung function through 60 months of age. METHODS: We included a cohort of 772 Mexican preschoolers whose mothers participated in a clinical trial (NCT00646360) of supplementation with DHA or a placebo from week 18-22 of gestation through delivery. MEASUREMENTS: The children were followed after birth and anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. The effect of DHA was tested using a longitudinal mixed effect models. RESULTS: Overall, mean (Standard Deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during follow up period were 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), -4.6 (1.6), respectively. There were no significant differences in pulmonary function by treatment group. DHA did not affect the average lung function or the trajectories through 60 months. CONCLUSIONS: Prenatal DHA supplementation did not influence pulmonary function in this cohort of Mexican preschoolers.

Serological Evidence of Lyssavirus Infection among Bats in Nagaland, a North-Eastern State in India.

Bats are known to be reservoirs of several medically important viruses including lyssaviruses. However, no systematic surveillance for bat rabies has been carried out in India, a canine rabies endemic country with a high burden of human rabies. Surveillance for rabies virus (RABV) infection in bats was therefore carried out in Nagaland, a north-eastern state in India at sites with intense human-bat interfaces during traditional bat harvests. Brain tissues and sera from bats were tested for evidence of infection due to RABV. Brain tissues were subjected to the fluorescent antibody test for detection of viral antigen and real-time reverse transcriptase PCR for presence of viral RNA. Bat sera were tested for the presence of rabies neutralizing antibodies by the rapid fluorescent focus inhibition test. None of the bat brains tested (n = 164) were positive for viral antigen or viral RNA. However, rabies neutralizing antibodies were detected in 4/78 (5·1%) bat sera tested, suggesting prior exposure to RABV or related lyssaviruses. The serological evidence of lyssaviral infection in Indian bats may have important implications in disease transmission and rabies control measures, and warrant extensive bat surveillance to better define the prevalence of lyssaviral infection in bats.

Commensalism facilitates gene flow in mountains: a comparison between two Rattus species.

Small mammal dispersal is strongly affected by geographical barriers. However, commensal small mammals may be passively transported over large distances and strong barriers by humans (often with agricultural products). This pattern should be especially apparent in topographically complex landscapes, such as mountain ranges, where valleys and/or peaks can limit dispersal of less vagile species. We predict that commensal species would have lower genetic differentiation and higher migration rates than related non-commensals in such landscapes. We contrasted population genetic differentiation in two sympatric Rattus species (R. satarae and R. rattus) in the Western Ghats mountains in southern India. We sampled rats from villages and adjacent forests in seven locations (20-640 km apart). Capture-based statistics confirmed that R. rattus is abundant in human settlements in this region, whereas R. satarae is non-commensal and found mostly in forests. Population structure analyses using ~970-bp mitochondrial control region and 17 microsatellite loci revealed higher differentiation for the non-commensal species (R. satarae F-statistics=0.420, 0.065, R. rattus F-statistics=0.195, 0.034; mitochondrial DNA, microsatellites, respectively). Genetic clustering analyses confirm that clusters in R. satarae are more distinct and less admixed than those in R. rattus. R. satarae shows higher slope for isolation-by-distance compared with R. rattus. Although mode of migration estimates do not strongly suggest higher rates in R. rattus than in R. satarae, they indicate that migration over long distances could still be higher in R. rattus. We suggest that association with humans could drive the observed pattern of differentiation in the commensal R. rattus, consequently impacting not only their dispersal abilities, but also their evolutionary trajectories.

Cryptic diversity and habitat partitioning in an economically important aphid species complex.

Cardamom Bushy Dwarf Virus (CBDV) is an aphid-borne nanovirus which infects large cardamom, Amomum subulatum (Zingiberaceae family), in the Himalayan foothills of Northeast India, Nepal and Bhutan. Two aphid species have been reported to transmit CBDV, including Pentalonia nigronervosa and Micromyzus kalimpongensis (also described as Pentalonia kalimpongensis). However, P. nigronervosa was recently split into two species which exhibit different host plant affiliations. Whilst P. nigronervosa primarily feeds on banana plants, Pentaloniacaladii (previously considered a 'form' of P. nigronervosa) typically feeds on plants belonging to the Araceae, Heliconiaceae and Zingiberaceae families. This raises the possibility that CBDV vectors that were originally described as P. nigronervosa correspond to P. caladii. Accurate identification of vector species is important for understanding disease dynamics and for implementing management strategies. However, closely related species can be difficult to distinguish based on morphological characteristics. In this study, we used molecular markers (two mitochondrial loci and one nuclear locus) and Bayesian phylogenetic analyses to identify aphid specimens collected from 148 CBDV infected plants at a range of locations and elevations throughout Sikkim and the Darjeeling district of West Bengal (Northeast India). Our results revealed the presence of a diversity of lineages, comprising up to six distinct species in at least two related genera. These included the three species mentioned above, an unidentified Pentalonia species and two lineages belonging to an unknown genus. Surprisingly, P. caladii was only detected on a single infected plant, indicating that this species may not play an important role in CBDV transmission dynamics. Distinct elevation distributions were observed for the different species, demonstrating that the community composition of aphids which feed on large cardamom plants changes across an elevation gradient. This has implications for understanding how competent vector species could influence spatial and temporal transmission patterns of CBDV.

Multicausal etiology of anemia among women of reproductive age in Vietnam.

BACKGROUND/OBJECTIVES: Anemia is a significant public health concern, especially among women and young children. An improved understanding of the complex etiology of anemia is crucial for developing appropriate prevention strategies. This paper examines the determinants of anemia in a large sample of Vietnamese women of reproductive age (WRA). METHODS: We included baseline data from 4986 WRA participating in a randomized controlled trial (PRECONCEPT). Hemoglobin (Hb) concentrations were measured with Hemocue. Plasma ferritin (Fe), retinol binding protein (RBP) and markers of inflammation were assessed using the ELISA technique. We used multivariate logistic regression to describe associations with anemia and structural equation modeling (SEM) to characterize direct and indirect pathways influencing Hb concentrations. RESULTS: Prevalence of anemia, iron deficiency (Fe <12 µg/l), insufficient iron stores (Fe<30 µg/l) and iron deficiency anemia was 19.7, 3.5, 14.4 and 1.9%, respectively. Ferritin concentration (0.29 per log-mg/dl), being an ethnic minority (-0.24 compared with Kinh), number of children (-0.17) and socioeconomic status (0.09) were directly associated with Hb concentration (P<0.05). Similarly, RBP was directly (0.27 per mg/dl) associated with Hb and also indirectly (0.09 mg/dl) with ferritin. Hookworm infection was indirectly associated with Hb (-0.11) through RBP and ferritin. CONCLUSION: These findings illustrate the complex etiology of anemia and provide a useful framework for designing, targeting and evaluating appropriate strategies for the prevention and control of anemia. Contrary to expectations, iron deficiency accounted for a very small proportion of anemia in Northern Vietnam.

Asymmetric patterns of reassortment and concerted evolution in Cardamom bushy dwarf virus.

Nanoviruses are single-stranded DNA (ssDNA) plant viruses which have multipartite genomes consisting of discrete, individually encapsidated components. This multipartite strategy may lead to high rates of reassortment, whereby entire genome components are exchanged among different strains. However, few studies have explored the extent to which reassortment shapes the genetic diversity of nanovirus populations. Here we present an extensive analysis of reassortment among 163 Cardamom bushy dwarf virus (CBDV; Nanoviridae family, Babuvirus genus) isolates collected in Northeast India. We also examined evidence of recombination, which is known to play a role in the evolutionary dynamics of nanovirus populations. By sequencing six discrete genome components for each isolate, we demonstrate that over 40% of the isolates display evidence of at least one reassortment event during their evolutionary histories. Nevertheless, a bias in the frequencies at which different genome components reassort was observed, with the DNA-M and DNA-N components being the most predisposed to reassortment. This may reflect variation in the ability of different genome components to function efficiently in a foreign genomic background. Comparisons of the common regions of different genome components revealed signatures of concerted evolution mediated by frequent inter-component homologous recombination. This process, which has previously been reported in nanoviruses and other multipartite ssDNA viruses, may allow proteins which initiate replication to maintain control over distinct genome components. Notably, DNA-N, one of the genome components most prone to reassortment, also exhibited the most frequent inter-component homologous recombination. This supports the idea that inter-component homologous recombination may promote the efficient replication of novel components which are introduced into a genome via reassortment.

Early life growth trajectories and future risk for overweight.

OBJECTIVE: Standard approaches have found that rapid growth during the first 2 years of life is a risk factor for overweight in later childhood. Our objective was to test whether growth velocity, independent of concurrent size, was associated with overweight using a nonlinear random-effects model that allows for enhanced specifications and estimations. METHODS: Longitudinal data from a birth cohort in Mexico (n=586) were used to estimate growth trajectories over 0-24 months for body mass index (BMI), length and weight using the SuperImposition by Translation and Rotation (SITAR) models. The SITAR models use a nonlinear random-effects model to estimate an average growth curve for BMI, length and weight and each participant's deviation from this curve on three dimensions-size, velocity and timing of peak velocity. We used logistic regression to estimate the association between overweight status at 7-9 years and size, velocity and timing of BMI, length and weight trajectories during 0-24 months. We tested whether any association between velocity and overweight varied by relative size during 0-24 months or birth weight. RESULTS: SITAR models explained the majority of the variance in BMI (73%), height (86%) and weight (85%) between 0-24 months. When analyzed individually, relative BMI/length/weight (size) and BMI/length/weight velocity during 0-24 months were each associated with increased odds of overweight in late childhood. Associations for timing of peak velocity varied by anthropometric measure. However, in the mutually adjusted models, only relative BMI/length/weight (size) remained statistically significant. We found no evidence that any association between velocity and overweight varied by size during 0-24 months or birth weight. CONCLUSIONS: After mutual adjustment, size during 0-24 months of life (as opposed to birth size), but not velocity or timing of peak velocity, was most consistently associated with overweight in later childhood.

Associations between maternal prepregnancy body mass index and child neurodevelopment at 2 years of age.

OBJECTIVE: Both underweight and obese mothers have an increased risk for adverse offspring outcomes. Few studies have examined the association between prepregnancy body mass index (BMI) and children's neurodevelopment. SUBJECTS: We used data from the nationally representative Early Childhood Longitudinal Study-Birth Cohort (ECLS-B; n=6850). Children were classified according to their mother's prepregnancy BMI (kg m(-2)) status: underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), obese class I (BMI 30.0-34.9), and obese class II and III (BMI ≥35.0). Children's age-adjusted mental development index (MDI) and psychomotor development index (PDI) T-scores (mean 50, s.d. 10) were obtained using a validated shortened version of the Bayley Scales of Infant Development-II at approximately 2 years of age. While adjusting for sociodemographics, we estimated the average MDI and PDI scores or the risk of delayed (<-1 s.d. vs >1 s.d.) mental or motor development, relative to children of normal weight mothers. RESULTS: Compared with children of normal weight mothers, MDI scores were lower among children of mothers of all other prepregnancy BMI categories, with the greatest adjusted difference among children of class II and III obese mothers (-2.13 (95% CI -3.32, -0.93)). The adjusted risk of delayed mental development was increased among children of underweight (risk ratio (RR) 1.36 (95% CI 1.04, 1.78)) and class II and III obese (RR 1.38 (95% CI 1.03, 1.84)) mothers. Children's PDI scores or motor delay did not differ by maternal prepregnancy BMI. CONCLUSION: In this nationally representative sample of 2-year-old US children, low and very-high maternal prepregnancy BMI were associated with increased risk of delayed mental development but not motor development.

Determinants of effective population size for loci with different modes of inheritance.

Here we report an assessment of the determinants of effective population size (N(e)) in species with overlapping generations. Specifically, we used a stochastic demographic model to investigate the influence of different life-history variables on N(e)/N (where N = population census number) and the influence of sex differences in life-history variables on N(e) for loci with different modes of inheritance. We applied an individual-based modeling approach to two datasets: one from a natural population of savannah baboons (Papio cynocephalus) in the Amboseli basin of southern Kenya and one from a human tribal population (the Gainj of Papua New Guinea). Simulation-based estimates of N(e)/N averaged 0.329 for the Amboseli baboon population (SD = 0.116, 95% CI = 0.172 - 0.537) and 0.786 for the Gainj (SD = 0.184, 95% CI = 0.498 - 1.115). Although variance in male fitness had a substantial impact on N(e)/N in each of the two primate populations, ratios of N(e) values for autosomal and sex-linked loci exhibited no significant departures from Poisson-expected values. In each case, similarities in sex-specific N(e) values were attributable to the unexpectedly high variance in female fitness. Variance in male fitness resulted primarily from age-dependent variance in reproductive success, whereas variance in female fitness resulted primarily from stochastic variance in survival during the reproductive phase.

Iron deficiency anemia: higher prevalence in Mexican American than in non-Hispanic white females in the third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: Mexican American females have a higher prevalence of iron deficiency than do non-Hispanic white females. OBJECTIVE: The objective was to estimate the prevalence of iron deficiency anemia and examine potential reasons for this difference between Mexican American (n = 1194) and non-Hispanic white (n = 1183) females aged 12-39 y. DESIGN: We used data from the third National Health and Nutrition Examination Survey (1988-1994). Iron deficiency anemia was defined as abnormal results from >/=2 of 3 tests (erythrocyte protoporphyrin, transferrin saturation, and serum ferritin) and a low hemoglobin concentration. We used multiple logistic regression to adjust for factors that were more prevalent in Mexican American females and significantly associated with iron deficiency anemia. RESULTS: The prevalence of iron deficiency anemia was 6.2 +/- 0.8% (f1.gif" BORDER="0"> +/- SE) in Mexican American females and 2.3 +/- 0.4% in non-Hispanic white females. Mean dietary iron intake, mean serum vitamin C concentrations, and the proportion of females using oral contraceptives were similar in the 2 groups. Age <20 y and education were not associated with iron deficiency anemia. After adjustment for poverty level, parity, and iron supplement use, the prevalence of iron deficiency anemia was 2.3 times higher in Mexican American than in non-Hispanic white females (95% CI: 1.4, 3.9). In those with a poverty income ratio (based on household income) >3.0, however, the prevalence of iron deficiency anemia was 2.6 +/- 0.9% in Mexican American and 1.9 +/- 0.6% in non-Hispanic white females (NS). CONCLUSION: Although much of the ethnic disparity in iron deficiency anemia remains unexplained, factors associated with household income may be involved.

Co-occurrence of nutrition problems in Honduran children.

We used data from the 1996 Honduras National Micronutrient Survey to investigate the co-occurrence of vitamin A deficiency (VAD), anemia and stunting in a representative sample of Honduran children 1-5 y old. Observed frequencies of co-occurrence were compared with frequencies expected by chance in children 12-35.9 mo old (n = 633) and 36-59.9 mo old (n = 610) for the three possible two-way combinations of the problems and the three-way combination. Observed frequencies were greater than expected frequencies for all eight comparisons, and all comparisons except for that of stunting and anemia in younger children were significant. The observed frequency of the three-way co-occurrence was 8.4% compared with an expected co-occurrence of 8.1% in younger children (P: < 0.05) and 4.8% compared with 4.2%, respectively, in older children (P: < 0.001). Although there was statistical evidence for co-occurrence, differences between expected and observed prevalences were small for most comparisons. Our findings suggest that having one or two problems does not appreciably increase the probability of having another. The efficiency of nutrition interventions aimed at these conditions would not be improved by targeting children with any one of the conditions; rather, the three conditions should be treated as virtually independent when designing programs. Replication of this study in other settings is warranted.

Recognition of heterospecific alarm vocalizations by bonnet macaques (Macaca radiata).

Recognition of heterospecific alarm vocalizations is an essential component of antipredator behavior in several prey species. The authors examined the role of learning in the discrimination of heterospecific vocalizations by wild bonnet macaques (Macaca radiata) in southern India The bonnet macaques' flight and scanning responses to playbacks of their own alarm vocalizations were compared with their responses to playbacks of vocalizations of Nilgiri langurs (Trachypithecus johnii), Hanuman langurs (Semnopithecus entellus), and sambar deer (Cervus unicolor). The study was conducted in 3 regions that differed in the frequency with which bonnet macaques encountered these species and included an urban setting. Call recognition was highest in adults and in regions where individuals were frequently exposed to the calling species; calls were not recognized by urban monkeys. Thus, age and experience are important factors in heterospecific call recognition by bonnet macaques.

Early childhood nutrition, education and fertility milestones in Guatemala.

Data on fertility milestones were collected in 1994 and linked to information collected in a trial conducted in eastern Guatemala between 1969 and 1977, to examine whether early childhood nutrition was associated with the timing of fertility milestones. In the original trial, two pairs of villages were randomly allocated to receive either a high energy, high protein supplement (Atole) or a low energy, no-protein supplement (Fresco). Mean age at follow-up was 23.47 y (n = 240). About 62% of women had experienced first birth (median age at first birth = 19.83 y). The median intervals from menarche to first intercourse and from first intercourse to first birth were 5.67 and 0.95 y; they were 1.68 and 0.06 y shorter, respectively, for the Atole group than for the Fresco group. Women who had received Atole in utero and/or during early childhood experienced earlier milestones even after adjusting for socioeconomic status (SES), education and age at the prior event. Median age at first birth was 1.17 y earlier for the Atole group. Better growth during early childhood (not severely stunted) led to earlier milestones (median age at first birth was 1.04 y earlier), primarily among women with illiterate fathers. Completion of primary school significantly delayed fertility milestones; the median age at first birth was 4.27 y later for those who completed primary school compared with those who did not (P < 0.05). In sum, improved nutrition during early childhood results in earlier fertility milestones, but the effects of schooling in delaying fertility milestones are greater in magnitude. Intervention programs that improve early childhood nutrition should be accompanied by investments in education that ensure that girls complete primary school.

Dietary vitamin A intakes of preschool-age children in South India.

The vitamin A intake of children aged 1-3 y (n = 683) was assessed using a quantitative food-frequency questionnaire in a vitamin A intervention study in South India. Trained field workers interviewed mothers about their children's usual consumption of common sources of vitamin A and collected information on portion sizes using standard cups. Mothers were asked to state the number of months in a year during which specific seasonal foods were available. Information about current breast-feeding was also obtained. Vitamin A intakes from nonbreast milk sources were extremely low at all ages. The median intake of total vitamin A, beta-carotene and retinol was 121, 100 and 21 retinol equivalents (RE), respectively. Maternal education and socioeconomic status (SES) were positively associated with total vitamin A and retinol intakes. Girls had significantly lower intakes than boys even after adjusting for differences in age, maternal education, SES and breast-feeding status. Breast-feeding was common, but declined to 60% by 24 mo and to 15% by 36 mo. Vitamin A intakes from nonbreast milk sources increased with age only for currently breast-fed children, who tended to be of lower SES. After taking into account the potential contribution of breast milk by using published estimates, nonbreast-fed children met only 60% of the Indian recommended dietary allowance (RDA; 250 RE/d), whereas breast-fed children met approximately 90% of the RDA during y 2 of life.

Role of intergenerational effects on linear growth.

Current knowledge on the role of intergenerational effects on linear growth is reviewed on the basis of a literature search and recent findings from an ongoing study in Guatemala. Fourteen studies were identified, most of which examined the intergenerational relationships in birth weight. Overall, for every 100 g increase in maternal birth weight, her child's birth weight increased by 10-20 g. The study samples were primarily from developed countries, and birth weight data were extracted from hospital records and/or birth registries. Among the few studies that examined associations between the adult heights of parents and their offspring, correlation coefficients of 0.42-0.5 were reported. None of the studies examined intergenerational relationships in birth length or linear growth patterns during early childhood, preadolescence and/or adolescence. Prospectively collected data from long-term studies being carried out in rural Guatemala provide the first evidence of intergenerational relationships in birth size in a developing country setting. Data were available for 215 mother-child pairs. Maternal birth size was a significant predictor (P < 0.05) of child's birth size after adjusting for gestational age and sex of the child and other potential confounders. Child's birth weight increased by 29 g/100 g increase in maternal birth weight which is nearly twice that reported in developed countries. Similarly, child's birth length increased by 0.2 cm for every 1 cm increase in mother's birth length. The effect of maternal birth weight remained significant even after adjusting for maternal adult size. More evidence from developing countries will help explain the underlying mechanisms and identify appropriate interventions to prevent growth retardation.

The role of vitamin A in reducing child mortality and morbidity and improving growth.

This is an update of knowledge on the role of the vitamin A status in determining child mortality, morbidity and growth. Recent information confirms the earlier conclusion of Beaton et al. that a 23% reduction in young child mortality results following improvements in the vitamin A status. Studies show that the mortality effect is primarily due to reductions in deaths due to acute gastroenteritis and measles but not acute respiratory infections (ARI) and malaria. While improvement of the vitamin A status enhances the survival of older preschool children, it remains unclear whether it benefits infants (i.e. < 6 months). Vitamin A supplementation does not reduce the overall incidence and prevalence of common childhood illness; however, it reduces the incidence of more severe episodes of diarrhea. Also, vitamin A supplementation either during and/or immediately after the illness does not improve its symptomatology. Finally, contrary to earlier expectations, recently completed, placebo-controlled randomized interventions have failed to detect improvements in child growth.