Biomedical subjects

Chittaranjan Yajnik

Publications and source records attributed to Chittaranjan Yajnik.

6 recordsLinked to original sources

PubMed2006

Geographical variation in relationships between parental body size and offspring phenotype at birth.

BACKGROUND: Size and body proportions at birth are partly determined by maternal body composition, but most studies of mother-baby relationships have only considered the effects of maternal height and weight on offspring birth weight, and few have examined the size of effects. Paternal size and body composition also play a role, primarily through the fetal genome, although few studies have investigated relationships with neonatal phenotype. METHODS: Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria and Jamaica were used to investigate the effects of maternal measures (derived at 30 weeks' gestation, n=16,418), and also paternal size (n=3,733) on neonatal phenotype, for singleton, live-born, term births. RESULTS: After accounting for variation in maternal size and shape across populations, differences in neonatal phenotype were markedly reduced. Mother-baby relationships were similar across populations, although some were stronger in developing countries. Maternal height was generally the strongest predictor of neonatal length, maternal head circumference of neonatal head and maternal skinfold thickness of neonatal skinfolds. Relationships with maternal arm muscle area were generally weak. Effects of paternal height and body mass index were weaker than the equivalent maternal measurements in most studies. CONCLUSIONS: Differences in maternal body composition account for a large part of the geographical variation in neonatal phenotype. The size of the effects of all maternal measures on neonatal phenotype suggests that nutrition at every stage of the mother's life cycle may influence fetal growth. Further research is needed into father-baby relationships and the genetic mechanisms that influence fetal growth.

Adult↗

PubMed2006

Geographical variation in neonatal phenotype.

BACKGROUND: Recent studies have shown associations between size and body proportions at birth and health outcomes throughout the life cycle, but there are few data on how neonatal phenotype varies in different populations around the world. METHODS: Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria, and Jamaica (n=22,067) were used to characterize geographical differences in phenotype in singleton, live-born newborns. Measurements included birth weight, placental weight, length, head, chest, abdominal and arm circumferences, and skinfolds. RESULTS: Neonates in Europe were the largest, followed by Jamaica, East Asia (China), then Africa and South Asia. Birth weight varied widely (mean values 2,730-3,570 g), but in contrast, head circumference was similar in all except China (markedly smaller). The main difference in body proportions between populations was the head to length ratio, with small heads relative to length in China and large heads relative to length in South Asia and Africa. CONCLUSIONS: These marked geographical differences in neonatal phenotype need to be considered when investigating determinants of fetal growth, and optimal phenotype for short-term and long-term outcomes.

Anthropometry↗

PubMed2006

Nutritional control of fetal growth.

Maternal micronutrient nutrition is an important determinant of size and body composition of the fetus. Maternal iron, iodine, calcium, folate, vitamin A, and vitamin C nutrition all influence offspring size. The Pune Maternal Nutrition Study was designed to study the relationship between maternal nutrition and fetal growth, size at birth, and postnatal growth. Maternal circulating folate and vitamin C concentrations predicted larger offspring size, while higher ferritin levels predicted smaller-sized babies. Subclinical vitamin B12 deficiency is common in India, especially in vegetarians, and children born to mothers with the lowest vitamin B12 but the highest folate status were the most adipose and the most insulin resistant. Furthermore, the relationship between maternal nutrition, fetal growth, and risk of type 2 diabetes and coronary heart disease appears to be much more complex than the simplistic postulates of the "fetal origins" hypothesis.

Ascorbic Acid↗

PubMed2004

Body size, body composition, and fat distribution: a comparison of young New Zealand men of European, Pacific Island, and Asian Indian ethnicities.

AIMS: To investigate body size and body fat relationships and fat distribution in young healthy men drawn from New Zealand European, Pacific Island, and Asian Indian populations. METHOD: A total of 114 healthy men (64 European, 31 Pacific Island, 19 Asian Indian) aged 17-30 years underwent measurements of height, weight, and body composition by total body dual-energy X-ray absorptiometry (DXA). Body mass index (BMI) was then calculated. Percent body fat (%BF), fat-free mass, bone mineral content, bone mineral density, abdominal fat, thigh fat, and appendicular skeletal muscle mass (ASMM) were obtained from the DXA scans. RESULTS: For the same BMI, %BF for Pacific Island men was 4% points lower and for Asian Indian men was 7-8% points higher compared to Europeans. Compared to European men for the same %BF, BMI was 2-3 units higher for Pacific Island, and 3-6 units lower for Asian Indian. The ratio of abdominal fat to thigh fat, adjusted for height, weight, and %BF, was significantly higher for Asian Indian men than European (p=0.022) and Pacific Island (p=0.002) men. ASMM, adjusted for height and weight, was highest in Pacific Island and lowest in Asian Indian men. CONCLUSIONS: The relationship between %BF and BMI is different for European, Pacific Island, and Asian Indian men which may, at least in part, be due to differences in muscularity. Asian Indians have more abdominal fat deposition than their European and Pacific Island counterparts. Use of universal BMI cut-off points are not appropriate for comparison of obesity prevalence between these ethnic groups.

Adolescent↗

PubMed2004

Report on the 2nd World Congress on Fetal Origins of Adult Disease, Brighton, U.K., June 7-10, 2003.

In 1989, reports suggested that the fetal environment, as reflected in birth size, was related to the risk of noncommunicable diseases in adult life. This association was first described for coronary heart disease but rapidly extended to include type 2 diabetes, osteoporosis, and metabolic and endocrine homeostasis. This led to the development of the fetal origins of adult disease paradigm, which resulted in a refocusing of research effort over the next 10 y to consider the lifelong consequences of perinatal influences on chronic diseases. Previously, perinatal influences had largely been seen in terms of teratogenic effects or acute birth injury rather than whether trajectories and responses made during early development had lifelong consequences. Indeed, in developmental biology, it is widely recognized that adaptive plastic responses during early development often have consequences for function in later adulthood. Although the relative importance of this newly recognized set of phenomena to the burden of human disease has been controversial, the research precipitated by those early observations has confirmed their robustness and started to provide a mechanistic basis to this biology. Two world congresses have been held to review progress in this research. Both have been characterized by a unique multidisciplinary attendance ranging from molecular, experimental, and developmental biologists to epidemiologists and health economists.

Adult↗

PubMed2002

Application of stable isotopic techniques in the prevention of degenerative diseases like obesity and NIDDM in developing societies.

Economic development in developing societies characterized by industrialization, urbanization, and globalization has seen the emergence of an epidemic of diet- and life-style-related chronic degenerative diseases. A research project was initiated under the aegis of the International Atomic Energy Agency (IAEA), Vienna, Austria under its Coordinated Research Programme (CRP) to promote the use of stable isotopic techniques to document the extent of the problem and to understand the determinants of this epidemic. The principal objectives of this CRP involving countries both in the North and the South are to define the magnitude of the problem of obesity and non-insulin dependent diabetes mellitus (NIDDM) in developing countries, to identify the vulnerable groups at increased risk, and to attempt to describe the metabolic and physiological mechanisms underlying this phenomenon. These comparative international studies of obesity and NIDDM are looking at the effects of childhood malnutrition (Brazil) and socioeconomic differentials (Mexico) on adult risk factors; the composition of the daily diet on obesity (Chile); levels of patterns of physical activity of older adults (China) as well as their influence on weight gain and obesity (Cuba, Nigeria); the impact of body composition and energy expenditure on the evolution frank diabetes from impaired glucose tolerance (Jamaica), and of body compositional changes and the role of inflammatory cytokines on impaired glucose tolerance (India). The last study conducted in New Zealand was aimed at comparing the energy expenditures of Maori (Pacific Island) with New Zealanders of European descent.

Africa↗