Trends in Height and BMI of 6‐Year‐Old Children during the Nutrition Transition in Chile

Objective: We analyzed trends in height and BMI and their interaction in 6‐year‐old Chilean children over the last 15 years. Research Methods and Procedures: We calculated height for age z‐score (HAZ), BMI z‐score, prevalence of obesity, underweight, and stunting from cross‐sectional national school‐based annual population surveys in 1987, 1990, 1993, 1996, 2000, and 2002. Using mixed model analysis, we determined the risk of obesity according to height over time as odds ratios (ORs) and 95% confidence interval and the potential influence of height and year of study on BMI z‐score. Results: Over the study period, height increased by 2.8 cm in boys and 2.6 cm in girls, whereas stunting declined from 5% to 2% in both. Tallness increased by ～2%, BMI z‐score increased from +0.3 to +0.65 in boys and to +0.62 in girls, and HAZ increased from ?0.47 in boys and ?0.45 in girls to 0 in 2002. Underweight declined from 4% to 3%, whereas obesity rose from 5% to ～14%. The probability of obesity among tall children was significantly greater than that for normal height children (OR, 2.3 to 3.5). The lowest obesity risk was observed between ?2 and ?1 HAZ. The OR for obesity in the stunted relative to normal height children was variable, ranging from 1.23 to 0.65, whereas it was significant and consistently positive (1.1 to 1.7) for boys and girls when it was compared with the lowest obesity risk according to height. Discussion: Tallness is significantly associated with increased obesity risk in children, while stunting is also associated, but to a lesser degree.     

Significant sex difference in the association between C‐reactive protein concentration and anthropometry among 13‐ to 19‐year olds,but not 6‐ to 12‐year olds in Nepal

Life history theory predicts a trade‐off between immunostimulation and growth. Using a cross‐sectional study design, this study aims to test the hypothesis that C‐reactive protein (CRP) is negatively associated with height‐for‐age z‐scores (HAZ scores) and BMI‐for‐age z‐scores (BAZ scores) among 6‐ to 19‐year olds (N = 426) residing in five Nepalese communities. Dried blood spot (DBS) samples were collected and assayed for CRP using an in‐house enzyme immunoassay (EIA). Sex‐ and age‐group‐specific CRP quartiles were used to examine its association with growth in linear mixed‐effects (LME) models. A significant difference was found in the proportion of elevated CRP (>2 mg/L, equivalent to ～3.2 mg/L serum CRP) between 13‐ and 19‐year‐old boys (12%) and girls (4%). Concentrations of CRP were positively associated with HAZ score among adolescent (13–19 years) boys, which may indicate that individuals with greater energy resources have better growth and a better response to infections, thus eliminating the expected trade‐off between body maintenance (immunostimulation) and growth. Adolescent boys with low BAZ and HAZ scores had low CRP values, suggesting that those who do not have enough energy for growth cannot increase their CRP level even when infected with pathogens. Among adolescent girls a positive association was observed between CRP and BAZ scores suggesting the possible effects of chronic low‐grade inflammation due to body fat rather than infection. The association between CRP and growth was less evident among children (6–12 years) compared with adolescents, indicating that the elevated energy requirement needed for the adolescent growth spurt and puberty may play some role. Am J Phys Anthropol 154:42–51, 2014. © 2014 Wiley Periodicals, Inc.     

Height and BMI of Italian immigrants to the USA, 1908–1970

We analyze self-reported anthropometric data pertaining to 2140 adults who emigrated to the United States, mainly from southern Italy, between 1908-1928 and 1960-1970. The mean height of immigrant men was 165.5 cm: they were taller than contemporary southern Italian men by 0.5-7.3 cm in different periods. The mean height of the Italian immigrant women born before 1952 was 157.6 cm, less than the national average. At the end of the 1990s, national women average height was 162 cm, 159.5 cm for southern women. There were age-related increases of weight and BMI: overweight was more prevalent in the 40-49 years age category. In the male sample, the mean values of BMI were within the overweight range in all age classes. The prevalence of obesity was higher in the male sample than among US men, whereas it was virtually identical in the women's sample and much higher than the values reported for several European countries for the period 1970-1980.     

Relationship between Body Mass Index and Percent Body Fat in Vietnamese: Implications for the Diagnosis of Obesity

BackgroundThe burden of obesity in Vietnam has not been well defined because there is a lack of reference data for percent body fat (PBF) in Asians. This study sought to define the relationship between PBF and body mass index (BMI) in the Vietnamese population.MethodsThe study was designed as a comparative cross-sectional investigation that involved 1217 individuals of Vietnamese background (862 women) aged 20 years and older (average age 47 yr) who were randomly selected from the general population in Ho Chi Minh City. Lean mass (LM) and fat mass (FM) were measured by DXA (Hologic QDR 4500). PBF was derived as FM over body weight.ResultsBased on BMI ≥30, the prevalence of obesity was 1.1% and 1.3% for men and women, respectively. The prevalence of overweight and obesity combined (BMI ≥25) was ~24% and ~19% in men and women, respectively. Based on the quadratic relationship between BMI and PBF, the approximate PBF corresponding to the BMI threshold of 30 (obese) was 30.5 in men and 41 in women. Using the criteria of PBF >30 in men and PBF >40 in women, approximately 15% of men and women were considered obese.ConclusionThese data suggest that body mass index underestimates the prevalence of obesity. We suggest that a PBF >30 in men or PBF >40 in women is used as criteria for the diagnosis of obesity in Vietnamese adults. Using these criteria, 15% of Vietnamese adults in Ho Chi Minh City was considered obese.     

Detecting Body Fat–A Weighty Problem BMI versus Subcutaneous Fat Patterns in Athletes and Non-Athletes

We aimed to describe the relationship between BMI and the subcutaneous adipose tissue topography within young athletes and non-athletic controls, to comparatively evaluate the diagnostic powers of subcutaneous adipose tissue thicknesses at different body sites, furthermore to explore appropriate cut-offs to discriminate between athletes and controls. Measurements were determined in 64 males and 42 females, who were subsequently separated into two even groups (athletes and non-athletes). The optical device LIPOMETER was applied at standardised body sites to measure the thickness of subcutaneous adipose tissue layers. To calculate the power of the different body sites and the BMI to discriminate between athletes and non-athletes, receiver operating characteristic curve analysis was performed. In men, the neck (optimal cut-off value 2.3 mm) and trunk (optimal cut-off value 15.5 mm) provided the strongest discrimination power: with 90.6% (58 of 64) of the subjects being correctly classified into athletes or non-athletes. Discrimination power of the BMI values was 64.1% (41 of 64 were correctly classified). In women, the upper back (optimal cut-off value 3.3 mm) and arms (optimal cut-off value 15.9 mm) provided the strongest discrimination power with 88.1% (37 of 42 being correctly classified). When using BMI to discriminate between athletes and non-athletes only 52.4% (22 of 42) were correctly classified. These results suggest that compared to BMI levels, subcutaneous fat patterns are a more accurate way of discriminating between athletes and non-athletes. In particular the neck and the trunk compartment in men and the upper back and arms compartment in women, were the best sites to discriminate between young athletes and non-athletes on the basis of their fat patterns.     

Assessing Body Composition among 3‐ to 8‐Year‐Old Children: Anthropometry,BIA, and DXA

Objective: To examine the inter‐relationships of body composition variables derived from simple anthropometry [BMI and skinfolds (SFs)], bioelectrical impedance analysis (BIA), and dual energy x‐ray (DXA) in young children. Research Methods and Procedures: Seventy‐five children (41 girls, 34 boys) 3 to 8 years of age were assessed for body composition by the following methods: BMI, SF thickness, BIA, and DXA. DXA served as the criterion measure. Predicted percentage body fat (%BF), fat‐free mass (FFM; kilograms), and fat mass (FM; kilograms) were derived from SF equations [Slaughter (SL)1 and SL2, Deurenberg (D) and Dezenberg] and BIA. Indices of truncal fatness were also determined from anthropometry. Results: Repeated measures ANOVA showed significant differences among the methods for %BF, FFM, and FM. All methods, except the D equation (p = 0.08), significantly underestimated measured %BF (p < 0.05). In general, correlations between the BMI and estimated %BF were moderate (r = 0.61 to 0.75). Estimated %BF from the SL2 also showed a high correlation with DXA %BF (r = 0.82). In contrast, estimated %BF derived from SFs showed a low correlation with estimated %BF derived from BIA (r = 0.38); likewise, the correlation between DXA %BF and BIA %BF was low (r = 0.30). Correlations among indicators of truncal fatness ranged from 0.43 to 0.98. Discussion: The results suggest that BIA has limited utility in estimating body composition, whereas BMI and SFs seem to be more useful in estimating body composition during the adiposity rebound. However, all methods significantly underestimated body fatness as determined by DXA, and, overall, the various methods and prediction equations are not interchangeable.     

Percent Body Fat and Lean Mass Explain the Gender Difference in Leptin: Analysis and Interpretation of Leptin in Hispanic and Non‐Hispanic White Adults

Objective: To reassess the relationship between body fat and fasting leptin concentrations comparing plasma vs. serum assessments of leptin; ratios vs. regression adjustment for body composition; fat and lean mass vs. percent body fat; and gender‐, ethnic‐, and age‐related variations. Research Methods and Procedures: Subjects included 766 adults from the nondiabetic cohort of the San Luis Valley Diabetes Study examined at follow up (1997 to 1998). Body composition was determined by dual energy X‐ray absorptiometry. Leptin concentrations were determined after an overnight fast. Results: Fasting serum and plasma assessments of leptin were correlated with percent body fat to the same degree. Women had significantly higher serum leptin concentrations than men when leptin concentrations were divided by body mass index, fat mass in kilograms or percent body fat. The methodological problem inherent in interpreting these ratio measures is pictorially demonstrated. In regression analysis, fat mass alone did not explain the gender difference. However, lean body mass was inversely related to leptin concentrations (p < 0.0001) and explained 71% of the gender difference at a given fat mass. Percent body fat explained all of the gender difference in leptin concentrations in both Hispanics and non‐Hispanic whites. Similar to findings about gender differences, ethnic‐ and age‐related variations in the leptin‐body fat association were minimized when percent body fat was employed as the body fat measure. Discussion: Regression analysis and percent body fat measured with dual energy X‐ray absorptiometry are recommended when assessing the relationship between leptin and body fat. Gender differences in leptin concentrations were accounted for by percent body fat in free living (no diet control), Hispanic and non‐Hispanic white adults.     

Sex Differences in Regional Body Fat Distribution From Pre‐ to Postpuberty

Few large studies have evaluated the emergence of sexual dimorphism in fat distribution with appropriate adjustment for total body composition. The objective of this study was to determine the timing and magnitude of sex differences in regional adiposity from early childhood to young adulthood. Regional fat distribution was measured using dual‐energy X‐ray absorptiometry (trunk and extremity fat using automatic default regions and waist and hip fat using manual analysis) in 1,009 predominantly white participants aged 5–29 years. Subjects were divided into pre (Tanner stage 1), early (Tanner stages 2–3), late (Tanner stages 4–5), and post (males ≥20 years and females ≥18 years) pubertal groups. Sexual dimorphism in trunk fat (adjusted for extremity fat) was not apparent until late puberty, when females exhibited 17% less (P < 0.001) trunk fat than males. By contrast, sex differences in waist fat (adjusted for hip fat) were apparent at each stage of puberty, the effect being magnified with age, with prepubertal girls having 5% less (P = 0.027) and adult women having 48% less (P < 0.0001) waist fat than males. Girls had considerably more peripheral fat whether measured as extremity or hip fat at each stage. Sex differences in regional adiposity were significantly greater in young adults than in late adolescence. Exclusion of overweight participants did not materially affect the estimates. Sexual dimorphism in fat patterning is apparent even prepubertally with girls having less waist and more hip fat than boys. The magnitude of the sex difference is amplified with maturation, and particularly from late puberty to early adulthood.     

Body Fat and Fat‐Free Mass and All‐Cause Mortality

Objective: To investigate whether the association between BMI and all‐cause mortality could be disentangled into opposite effects of body fat and fat‐free mass (FFM). Research Methods and Procedures: All‐cause mortality was studied in the Danish follow‐up study “Diet, Cancer and Health” with 27, 178 men and 29, 875 women 50 to 64 years old recruited from 1993 to 1997. By the end of year 2001, the median follow‐up was 5.8 years, and 1851 had died. Body composition was assessed by bioelectrical impedance. Cox regression models were used to estimate the relationships among body fat mass index (body fat mass divided by height squared), FFM index (FFM divided by height squared), and mortality. All analyses were adjusted for smoking habits. Results: Men and women showed similar associations. J‐shaped associations were found between body fat mass index and mortality adjusted for FFM and smoking. The mortality rate ratios in the upper part of body fat mass were 1.12 per kg/m² (95% confidence interval: 1.07, 1.18) in men and 1.06 per kg/m² (95% confidence interval: 1.02, 1.10) in women. Reversed J‐shaped associations were found between FFM index and mortality with a tendency to level off for high values of FFM. Discussion: Our findings suggest that BMI represents joint but opposite associations of body fat and FFM with mortality. Both high body fat and low FFM are independent predictors of all‐cause mortality.     

Linking ‘10‐year’ herbivore cycles to the lunisolar oscillation: the cosmic ray hypothesis

The mean population cycle periods of the snowshoe hare Lepus americanus, the larch budmoth Zeiraphera diniana, and the autumnal moth Epirrita autumnata are 9.3 years, similar to the lunar nodal phase cycle. When the full/new Moon is situated close to the ecliptic plane at solstice, it interacts more strongly with the magnetosphere, which plays a crucial role in protecting the Earth against ionizing cosmic ray particles. Ionization by cosmic rays induces protein mobilization in plants, which may increase forage quality for herbivores. Series of hare/lynx population indices from Canadian provinces and an autumnal moth series from Fennoscandia correlated with the lunar nodal phase cycle with different time lags. Both the time lag and the impact of an active sun, which increases solar energetic particles, but decreases galactic cosmic ray particles, were related to radiation or the distance from the auroral oval. These insights improve our ability to explain and understand population peaks, and should also motivate further studies on the effects of cosmic rays on plant chemistry and herbivore performance.     

Synthesis of 8‐Substituted 2′‐Deoxyisoguanosines via Unprotected 8‐Brominated 2‐Amino‐2′‐deoxyadenosine

A variety of applications of 8‐alkynylated nucleosides has prompted the synthesis of new purine analogues. Bromination of unprotected 2‐amino‐2′‐deoxyadenosine with Br₂/AcOH/AcONa gives 2‐amino‐8‐bromo‐2′‐deoxyadenosine (87%). The brominated derivative is converted to 8‐alkynylated 2‐amino‐2′‐deoxyadenosines by palladium‐catalyzed Sonogashira cross‐coupling reaction via microwave assistance (81 – 95%). The resulting compounds are further transformed to 8‐alkynylated 2′‐deoxyisoguanosines (52 – 70%). The physical properties of new compounds are investigated.     

Evolution of morphogenesis in 360‐million‐year‐old conodont chordates calibrated in days

SUMMARY Highly rhythmic increments of crown tissue are identifiable in conodont oral apparatus elements from the Late Devonian of the Holy Cross Mountains, Poland; individual laminae being of thickness comparable with daily increments of vertebrate tooth enamel and fish otoliths. Abundant occurrence of such specimens enables bed‐by‐bed (stratophenetic) studies of the process of evolution at the population level and quantitative presentation of the evolution of ontogeny in the sampled geological section covering several million years. The morphologic transformation is expressed as expansion of a juvenile asymmetry to later stages of the ontogeny and in decrease of the mature element width, which was due to a change of the mineral tissue secretion rate. It was not just a simple extension of a juvenile character into the later stage of the ontogeny (heterochrony) but rather a true developmental novelty. The evolution was gradual and very slow. The proposed quantitative approach to growth increments in the mineral skeleton of ancient chordates introduces real‐time units to evolutionary developmental studies connected with direct paleontological evidence on the course of evolution.     

Similarity in Percent Body Fat Between White and Vietnamese Women: Implication for a Universal Definition of Obesity

It has been widely assumed that for a given BMI, Asians have higher percent body fat (PBF) than whites, and that the BMI threshold for defining obesity in Asians should be lower than the threshold for whites. This study sought to test this assumption by comparing the PBF between US white and Vietnamese women. The study was designed as a comparative cross‐sectional investigation. In the first study, 210 Vietnamese women ages between 50 and 85 were randomly selected from various districts in Ho Chi Minh City (Vietnam). In the second study, 419 women of the same age range were randomly selected from the Rancho Bernardo Study (San Diego, CA). In both studies, lean mass (LM) and fat mass (FM) were measured by dual‐energy X‐ray absorptiometry (DXA) (QDR 4500; Hologic). PBF was derived as FM over body weight. Compared with Vietnamese women, white women had much more FM (24.8 ± 8.1 kg vs. 18.8 ± 4.9 kg; P < 0.0001) and greater PBF (36.4 ± 6.5% vs. 35.0 ± 6.2%; P = 0.012). However, there was no significant difference in PBF between the two groups after matching for BMI (35.1 ± 6.2% vs. 35.0 ± 5.7%; P = 0.87) or for age and BMI (35.6 ± 5.1% vs. 35.8 ± 5.9%; P = 0.79). Using the criteria of BMI ≥30, 19% of US white women and 5% of Vietnamese women were classified as obese. Approximately 54% of US white women and 53% of Vietnamese women had their PBF >35% (P = 0.80). Although white women had greater BMI, body weight, and FM than Vietnamese women, their PBF was virtually identical. Further research is required to derive a more appropriate BMI threshold for defining obesity for Asian women.