Biodiversity assessment and conservation strategies

The efficient representation of all species in conservation planning is problematic. Often, species distribution is assessed by dividing the land into a grid; complementary sets of grids, in which each taxon is represented at least once, are then sought. To determine if this approach provides useful surrogate information, species and higher taxon data for South African plants and animals were analyzed. Complementary species sets did not coincide and overlapped little with higher taxon sets. Survey extent and taxonomic knowledge did not affect this overlap. Thus, the assumptions of surrogacy, on which so much conservation planning is based, are not supported.

Impact of maternal body mass index on neonate birthweight and body composition

OBJECTIVE

The purpose of this study was to compare bodyweight and composition (percent fat, fat mass, and fat-free mass) in neonates born to mothers with a normal pregravid body mass index (BMI; < 25 kg/m(2)) vs neonates born to mothers with an overweight/obese pregravid BMI (> or = 25 kg/m(2)).

STUDY DESIGN

Seventy-two neonates (33 from normal mothers and 39 from overweight/obese mothers) of singleton pregnancies with normal glucose tolerance had their bodyweight and body composition assessed by air-displacement plethysmography.

RESULTS

After controlling for neonate age at time of testing, significant differences were found between groups for percent fat (12.5 +/- 4.2% vs 13.6 +/- 4.3%; P < or = .0001), fat mass (414.1 +/- 264.2 vs 448.3 +/- 262.2 g; P < or = .05), and fat-free mass (3310.5 +/- 344.6 vs 3162.2 +/- 343.4 g; P < or = .05), with no significant differences between birth length (50.7 +/- 2.6 vs 49.6 +/- 2.6 cm; P = .08) or birthweight (3433.0 +/- 396.3 vs 3368.0 +/- 399.6 g; P = .44).

CONCLUSION

Neonates born to mothers who have a normal BMI have significantly less total and relative fat and more fat-free mass than neonates born to overweight/obese mothers. Although preliminary, these data suggest that the antecedents of future disease risk (eg, cardiovascular disease, diabetes, and obesity) occur early in life.

Higher infant body fat with excessive gestational weight gain in overweight women

OBJECTIVE

Gestational weight gain (GWG) is positively associated with birthweight and maternal prepregnancy body mass index (BMI) is directly related to infant fat mass (FM). This study examined whether differences exist in infant body composition based on 2009 GWG recommendations.

STUDY DESIGN

Body composition was measured in 306 infants, and GWG was categorized as appropriate or excessive. Analysis of covariance was used to investigate the effects of GWG and prepregnancy BMI and their interaction on infant body composition.

RESULTS

Within the appropriate group, infants from obese mothers had greater percent fat (%fat) and FM than offspring from normal and overweight mothers. Within the excessive group, infants from normal mothers had less %fat and FM than infants from overweight and obese mothers. A difference was found for %fat and FM within the overweight group between GWG categories.

CONCLUSION

Excessive GWG is associated with greater infant body fat and the effect is greatest in overweight women.

iDXA, Prodigy, and DPXL dual-energy X-ray absorptiometry whole-body scans: a cross-calibration study

PURPOSE

Total body fat, lean, and bone mineral content (BMC) in addition to regional fat and lean mass values for arms, legs, and trunk were compared across a pencil-beam (Lunar DPXL) and 2 fan-beam (GE Lunar Prodigy and GE Lunar iDXA) dual-energy X-ray absorptiometry (DXA) systems.

METHODS

Subjects were a multiethnic sample of 99 healthy adult males (47%) and females (mean+/-SD: age, 46.3+/-16.9 yr; weight, 73.4+/-16.6 kg; height, 167.6+/-9.7 cm; body mass index, 26.0+/-5.2 kg/m2) who had whole-body scans performed within a 3-h period on the 3 systems. Repeated measures ANOVA was used to test the null hypothesis that the mean values for the 3 systems were equal. Translation equations between the methods were derived using regression techniques.

RESULTS

Bone mineral content (BMC): For both genders, total BMC by iDXA was lower (p<or=0.004) than the other systems. Lean: for males, iDXA was lower (p<or=0.03) than the other systems for total, trunk, and arms. For females, DPXL estimated higher (p<0.001) lean mass compared with the other systems for total, trunk, and arms, but iDXA estimated greater legs lean mass. For both genders, all DPXL mean values were greater than Prodigy mean values (p<0.001). Fat: in females, all the 3 systems were different from each other for total, trunk, and legs (p<or=0.04). For arms, DPXL and iDXA were higher than Prodigy (p<0.0004). For males, DPXL was less (p<0.001) for total body, trunk, and legs compared with the other 2 systems and greater than Prodigy only for arms (p<0.0007). These data were used to derive translation equations between systems. For several measurements, the differences between systems were related to gender.

CONCLUSION

For estimation of BMC and body composition, there was high agreement between all DXA systems (R2=0.85-0.99). Even so, cross-calibration equations should be used to examine data across systems to avoid erroneous conclusions.

Longitudinal body composition of children born to mothers with normal weight, overweight, and obesity

OBJECTIVE

The longitudinal trajectories of body composition of children born to mothers with normal weight, overweight, and obesity have not been evaluated using precise body composition methods. This study investigated the relationship between maternal prepregnancy BMI and offspring body composition trajectories during the first 6 years of life.

METHODS

Healthy infants (N = 325) were assessed longitudinally (at ages 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, and 6 years) using dual-energy X-ray absorptiometry. Mixed-effects regression for repeated measures was used to model each continuous outcome as a function of maternal BMI and covariates (race, gestational age, birth weight, and mode of infant feeding).

RESULTS

Maternal obesity differentially impacted body fat, but not bone mineral content or density, of girls and boys. Boys born to mothers with obesity have higher body fat from ages 2-6 years compared to boys born to normal-weight and overweight mothers (P < 0.05), whereas body composition of girls born to mothers with obesity was not different across groups during the first 6 years of life (P > 0.05).

CONCLUSIONS

This clinical observational study demonstrates a sexual dimorphism in offspring body composition until age 6 years based on maternal BMI, with a greater effect of maternal adiposity seen in boys than in girls.

Fat-free mass index: changes and race/ethnic differences in adulthood

OBJECTIVE

Nutritional status is assessed by measuring BMI or percent body fat (%fat). BMI can misclassify persons who carry more weight as fat-free mass and %fat can be misleading in cases of malnutrition or in disease states characterized by wasting of lean tissue. The fat-free mass index (FFMI) is proposed to assess body composition in individuals who have a similar body composition but differ in height allowing identification of those suffering from malnutrition, wasting or those that possess a relatively high muscle mass. The purpose was to determine whether the FFMI differs in a group of racially/ethnically diverse adults.

DESIGN

Cross-sectional.

SUBJECTS

Subjects were a multi-ethnic sample (Caucasian, CA; African American, AA; Hispanic, HIS and Asian, AS) of 1339 healthy males (n = 480) and females (n = 859) ranging in age from 18-110 years. Total body fat, total fat-free mass and bone mineral density were estimated using dual energy X-ray absorptiometry.

RESULTS

FFMI differed among the four ethnic groups (P ≤ 0.05) for both genders. A curvilinear relationship was found between age and FFMI for both genders although the coefficients in the quadratic model differed between genders (P ≤ 0.001) indicating the rate of change in FFMI differed between genders. The estimated turning point where FFMI started to decline was in the mid 20s for male and mid 40s for female participants. An age × gender interaction was found such that the rate of decline was greater in male than female participants (P ≤ 0.001). For both genders, FFMI was greatest in AA and the least in AS (P ≤ 0.001). There was no significant interaction between race and age or age(2) (P = 0.06). However, male participants consistently had a greater FFMI than female participants (P ≤ 0.001).

CONCLUSIONS

These findings have clinical implications for identifying individuals who may not be recognized as being malnourished based on their BMI or %fat but whose fat-free mass corrected for height is relatively low.

Freshman 15: fact or fiction?

OBJECTIVE

The objective of this study was to investigate changes in body weight, BMI, body composition, and fat distribution among freshman women during their 1st year of college.

RESEARCH METHODS AND PROCEDURES

Freshman women during the 2004 to 2005 academic year were recruited to participate. The initial baseline visit occurred within the first 6 weeks of the fall 2004 semester, with the follow-up visit occurring during the last 6 weeks of the spring 2005 semester. At each visit, height, weight, BMI, waist and hip circumferences, and body composition (by DXA) were obtained.

RESULTS

One hundred thirty-seven participants completed both the fall and spring visits. Significant (p < 0.0001) increases between the fall and spring visits were observed for body weight (58.6 vs. 59.6 kg), BMI (21.9 vs. 22.3), percentage body fat (28.9 vs. 29.7), total fat mass (16.9 vs. 17.7 kg), fat-free mass (38.1 vs. 38.4 kg), waist circumference (69.4 vs. 70.3 cm), and hip circumference (97.4 vs. 98.6 cm), with no significant difference observed in the waist-to-hip ratio (0.71 vs. 0.71; p = 0.78).

DISCUSSION

Although statistically significant, changes in body weight, body composition, and fat mass were modest for women during their freshman year of college. These results do not support the purported "freshman 15" weight gain publicized in the popular media.

Investigation on Injury to Plants from Air Pollution in the Los Angeles Area

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The effect of the Thanksgiving holiday on weight gain

BACKGROUND

More people than ever are considered obese and the resulting health problems are evident. These facts highlight the need for identification of critical time periods for weight gain. Therefore the purpose was to assess potential changes that occur in body weight during the Thanksgiving holiday break in college students.

METHODS

94 college students (23.0 +/- 4.6 yrs, 72.1 +/- 14.0 kg, 172.6 +/- 9.3 cm, 24.0 +/- 3.9 kg/m2) reported to the human body composition laboratory at the University of Oklahoma following a 6-hour fast with testing occurring prior to, and immediately following the Thanksgiving holiday break (13 +/- 3 days). Body weight (BW) was assessed using a balance beam scale while participants were dressed in minimal clothing. Paired t-tests were used to assess changes in BW pre and post Thanksgiving holiday with additional analysis by gender, body mass index (BMI), and class standing (i.e. undergraduate vs. graduate).

RESULTS

Overall, a significant (P < 0.05) increase in BW was found between pre (72.1 kg) and post (72.6 kg) Thanksgiving holiday. When stratified by gender and class standing a significant (P < 0.05) increase in body weight was observed between the pre and post Thanksgiving holiday in males (0.6 kg), females (0.4 kg) and graduate students (0.8 kg). When participants were classified by BMI as normal or as overweight/obese, a significant 1.0 kg BW gain was found (P < 0.05) in the overweight/obese (>/=25 kg/m2) group compared to a non significant 0.2 kg gain in the normal group (<25 kg/m2).

CONCLUSION

These data indicate that participants in our study gained a significant amount of BW (0.5 kg) during the Thanksgiving holiday. While an increase in BW of half a kilogram may not be cause for alarm, the increase could have potential long-term health consequences if participants retained this weight gain throughout the college year. Additionally, because the overweight/obese participants gained the greatest amount of BW, this group may be at increased risk for weight gain and further obesity development during the holiday season.

An anthropometric model to estimate neonatal fat mass using air displacement plethysmography

BACKGROUND

Current validated neonatal body composition methods are limited/impractical for use outside of a clinical setting because they are labor intensive, time consuming, and require expensive equipment. The purpose of this study was to develop an anthropometric model to estimate neonatal fat mass (kg) using an air displacement plethysmography (PEA POD® Infant Body Composition System) as the criterion.

METHODS

A total of 128 healthy term infants, 60 females and 68 males, from a multiethnic cohort were included in the analyses. Gender, race/ethnicity, gestational age, age (in days), anthropometric measurements of weight, length, abdominal circumference, skin-fold thicknesses (triceps, biceps, sub scapular, and thigh), and body composition by PEA POD® were collected within 1-3 days of birth. Backward stepwise linear regression was used to determine the model that best predicted neonatal fat mass.

RESULTS

The statistical model that best predicted neonatal fat mass (kg) was: -0.012 -0.064*gender + 0.024*day of measurement post-delivery -0.150*weight (kg) + 0.055*weight (kg)2 + 0.046*ethnicity + 0.020*sum of three skin-fold thicknesses (triceps, sub scapular, and thigh); R2 = 0.81, MSE = 0.08 kg.

CONCLUSIONS

Our anthropometric model explained 81% of the variance in neonatal fat mass. Future studies with a greater variety of neonatal anthropometric measurements may provide equations that explain more of the variance.

Child-Specific Thoracic Gas Volume Prediction Equations for Air-Displacement Plethysmography

OBJECTIVE

To develop child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography in 6- to 17-year-old children.

RESEARCH METHODS AND PROCEDURES

Study 1 developed TGV prediction equations using anthropometric variables after completing a measured TGV and air-displacement plethysmography test in 224 healthy boys and girls (11.2 +/- 3.2 years, 45.3 +/- 18.7 kg, 149.9 +/- 18.5 cm). Study 2 cross-validated the prediction equations in a separate cohort of 62 healthy boys and girls (11.2 +/- 3.4 years, 44.2 +/- 15.3 kg, 149.4 +/- 19.3 cm).

RESULTS

In Study 1 (development of TGV prediction equations), the quadratic relationship using height as the independent variable and the measured TGV as the dependent variable yielded the highest adjusted R(2) and the lowest SE of estimate in both genders, thus producing the following prediction equations: TGV = 0.00056 x H(2) - 0.12422 x H + 8.15194 (boys) and TGV = 0.00044 x H(2) - 0.09220 x H + 6.00305 (girls). In Study 2 (cross-validation), no significant difference between the predicted and measured TGVs (-0.018 +/- 0.377 liters) was observed. The regression between the measured TGV and the predicted TGV yielded a slope and intercept that did not significantly differ from the line of identity. Prediction accuracy was good as indicated by a high R(2) (0.862) and low SE of estimate (0.369 liters).

DISCUSSION

The new child-specific TGV prediction equations accurately, precisely, and without bias estimated the actual TGV of 6- to 17-year-old children.

Validity of anthropometric equations to estimate infant fat mass at birth and in early infancy

BACKGROUND

In newborns and children, body fat estimation equations are often used at different ages than the age used to develop the equations. Limited validation studies exist for newborn body fat estimation equations at birth or later in infancy. The study purpose was to validate 4 newborn fat mass (FM) estimation equations in comparison to FM measured by air displacement plethysmography (ADP; the Pea Pod) at birth and 3 months.

METHODS

Ninety-five newborns (1-3 days) had their body composition measured by ADP and anthropometrics assessed by skinfolds. Sixty-three infants had repeat measures taken (3 months). FM measured by ADP was compared to FM from the skinfold estimation equations (Deierlein, Catalano, Lingwood, and Aris). Paired t-tests assessed mean differences, linear regression assessed accuracy, precision was assessed by R² and standard error of the estimate (SEE), and bias was assessed by Bland-Altman plots.

RESULTS

At birth, FM measured by ADP differed from FM estimated by Deierlein, Lingwood and Aris equations, but did not differ from the Catalano equation. At 3 months, FM measured by ADP was different from all equations. At both time points, poor precision and accuracy was detected. Bias was detected in most all equations.

CONCLUSIONS

Poor agreement, precision, and accuracy were found between prediction equations and the criterion at birth and 3 months.

Perioperative Immunonutrition Modulates Inflammatory Response after Radical Cystectomy: Results of a Pilot Randomized Controlled Clinical Trial

PURPOSE

Poor preoperative nutritional status is associated with a higher complication rate after radical cystectomy in patients with bladder cancer. Given the short interval between diagnosis and radical cystectomy, we compared the effect of short-term specialized immunonutrition to that of a standard oral nutritional supplement on the acute inflammatory response and arginine status in patients treated with radical cystectomy.

MATERIALS AND METHODS

In this prospective, randomized study in 29 men 14 received specialized immunonutrition and 15 received oral nutritional supplement. Each group drank 3 cartons per day for 5 days before and 5 days after radical cystectomy. The Th1-Th2 balance, plasma interleukin-6 and plasma amino acids were measured at baseline, intraoperatively and on postoperative days 2, 14 and 30. Body composition was measured by dual energy x-ray absorptiometry at baseline and on postoperative days 14 and 30. Differences in outcomes were assessed using the generalized linear mixed model.

RESULTS

In the specialized immunonutrition group there was a 54.3% average increase in the Th1-Th2 balance according to the tumor necrosis factor-α-to-interleukin-13 ratio from baseline to intraoperative day, representing a shift toward a Th1 response. In the oral nutritional supplement group the Th1-Th2 balance decreased 4.8%. The change in the Th1-Th2 balance between the specialized immunonutrition and oral nutritional supplement groups significantly differed (p <0.027). Plasma interleukin-6 was 42.8% lower in the specialized immunonutrition group compared to the oral nutritional supplement group on postoperative day 2 (p = 0.020). In the specialized immunonutrition group plasma arginine was maintained from baseline to postoperative day 2 and yet the oral nutritional supplement group showed a 26.3% reduction from baseline to postoperative day 2 (p = 0.0003). The change in appendicular muscle loss between the groups was not statistically significant.

CONCLUSIONS

Th1-to-Th2 ratios, peak interleukin-6 levels and plasma arginine suggest that consuming specialized immunonutrition counteracts the disrupted T-helper balance, lowers the inflammatory response and prevents arginine depletion due to radical cystectomy.

The effect of the holiday season on body weight and composition in college students

Background

With the rapid increase in obesity rates, determining critical periods for weight gain and the effects of changes in fat mass is imperative. The purpose of this study was to examine changes in body weight and composition over the holiday season (Thanksgiving through New Year's) in male and female college students.

Methods

Subjects completed three visits: the first occurred within 2 weeks prior to Thanksgiving, the second occurred within 5 to 7 days following Thanksgiving, and the third occurred within 10 days following New Year's Day. A total of 82 healthy male and female college age subjects participated. Body composition by dual energy x-ray absorptiometry (DXA) was assessed at visits 1 and 3 while body weight was assessed at all three visits.

Results

Average body weight remained relatively unchanged from pre-Thanksgiving to post-New Year's (71.3 ± 14 kg vs. 71.2 ± 15 kg; P = 0.71) and, in fact, a subset of normal weight subjects lost a significant amount of body weight. However, percent body fat (25.9 ± 9 %fat vs. 27.0 ± 9 %fat; P < 0.01) and fat mass (18.3 ± 8 kg and 19.1 ± 8 kg; P < 0.01) significantly increased from pre-Thanksgiving to post-New Year's while fat-free mass (48.7 ± 12 kg and 48.3 ± 11 kg; P = 0.08) was not significantly different than the post-New Year's. A significant positive relationship (P < 0.001) between the change in BMI and percent fat, total fat mass, total fat free mass, and trunk fat mass for the pre-Thanksgiving and post-New Year's visits were found. The same significant positive relationships (P < 0.001) were also observed between the change in body weight and percent fat, total fat mass, total fat free mass, and trunk fat mass.

Conclusion

Despite the fact that body weight remained unchanged over the course of the holiday season, a significant increase in %body fat and fat mass was observed. With recent evidence showing marked morbidity and mortality to be associated with increased body fat (particularly abdominal adiposity), results from this study suggest body weight alone may underestimate the potentially deleterious effects of the holiday season.

Percent body fat estimations in college women using field and laboratory methods: a three-compartment model approach

BACKGROUND

Methods used to estimate percent body fat can be classified as a laboratory or field technique. However, the validity of these methods compared to multiple-compartment models has not been fully established. This investigation sought to determine the validity of field and laboratory methods for estimating percent fat (%fat) in healthy college-age women compared to the Siri three-compartment model (3C).

METHODS

Thirty Caucasian women (21.1 +/- 1.5 yrs; 164.8 +/- 4.7 cm; 61.2 +/- 6.8 kg) had their %fat estimated by BIA using the BodyGramtrade mark computer program (BIA-AK) and population-specific equation (BIA-Lohman), NIR (Futrex(R) 6100/XL), a quadratic (SF3JPW) and linear (SF3WB) skinfold equation, air-displacement plethysmography (BP), and hydrostatic weighing (HW).

RESULTS

All methods produced acceptable total error (TE) values compared to the 3C model. Both laboratory methods produced similar TE values (HW, TE = 2.4%fat; BP, TE = 2.3%fat) when compared to the 3C model, though a significant constant error (CE) was detected for HW (1.5%fat, p 2.7%fat) compared to the 3C model. Additionally, the SF3JPW %fat estimation equation resulted in a significant CE (2.6%fat, p

CONCLUSION

Data suggest that the BP and HW are valid laboratory methods when compared to the 3C model to estimate %fat in college-age Caucasian women. When the use of a laboratory method is not feasible, NIR, BIA-AK, BIA-Lohman, SF3JPW, and SF3WB are acceptable field methods to estimate %fat in this population.

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Metal binding to the HIV nucleocapsid peptide

Co(II) and Zn(II) binding constants have been measured for binding to the HIV-1 nucleocapsid N-terminal metal binding domain (residues 1-18), using competition titration methods and monitoring Co(II) binding by visible absorbance spectroscopy. Enthalpies for binding were directly measured by isothermal titration colorimetry. The results are compared with recent studies of related systems, including a study of Zn(II) binding by the full length protein.

Validity of air-displacement plethysmography in the assessment of body composition changes in a 16-month weight loss program

OBJECTIVE

To compare the accuracy of air displacement plethysmography (ADP) and dual energy x-ray absorptionmetry (DXA) in tracking changes in body composition after a 16 month weight loss intervention in overweight and obese females.

METHODS

93 healthy female subjects (38.9 +/- 5.7 yr, 159.8 +/- 5.6 cm, 76.7 +/- 9.9 kg, 30.0 +/- 3.4 kg/m2) completed a 16 month weight loss intervention. Eligible subjects attended 15 treatment sessions occurring over the course of 4 months with educational content including topics relating to physical activity and exercise, diet and eating behavior, and behavior modification. In the remaining 12 months, subjects underwent a lifestyle program designed to increase physical activity and improve eating habits. Before and after the intervention, subjects had their percent body fat (%fat), fat mass (FM), and fat-free mass (FFM)) assessed by DXA and ADP.

RESULTS

Significant differences (p < or = 0.001) were found between DXA and ADP at baseline %fat (46.0 % fat vs. 42.0 % fat), FM (35.3 kg vs. 32.5 kg) and FFM (40.8 kg vs. 44.2 kg) as well as at post intervention for %fat (42.1% fat vs. 38.3 % fat), FM (30.9 kg vs. 28.4 kg) and FFM (41.7 kg vs. 44.7 kg). At each time point, ADP %fat and total FM was significantly lower (p < or = 0.001) than DXA while FFM was significantly higher (p < or = 0.001). However, both techniques tracked %fat changes similarly considering that there were no differences between the two means. Furthermore, a Bland-Altman analysis was performed and no significant bias was observed, thus demonstrating the ability of ADP to measure body fat across a wide range of fatness.

CONCLUSION

At baseline and post weight loss, a significant difference was found between ADP and DXA. However, the results indicate both methods are highly related and track changes in %fat similarly after a weight loss program in overweight and obese females. Additionally, the mean changes in %fat were similar between the two techniques, suggesting that ADP can be translated to its use in clinical practice and research studies as DXA currently is used.

Relationship of circulating adipokines to body composition in pregnant women

Circulating adipokines are associated with physiological and pathophysiological processes in both obesity and pregnancy. Obesity in pregnancy increases the risk of pregnancy complications and the majority of research uses body mass index (BMI) to assess fatness. Specific fat compartments are associated with obesity-induced health risks yet it is not known how abdominal fat mass in pregnancy is related to circulating adipokines. Plasma leptin, resistin, visfatin, and adiponectin were measured by immunoassay in healthy pregnant women of normal weight (BMI 18.5-24.9; n = 17) and overweight/obese pregnant women (BMI 25.0-40, n = 21) in the third trimester. Total body and abdominal subcutaneous and visceral fat mass were measured at 1-3 weeks postpartum. Overweight/obese women had greater total body fat (t = -6.210, P < 0.001) and abdominal subcutaneous fat (t = -5.072, P < 0.001) than normal-weight women while there was no difference in abdominal visceral fat. Overweight/obese women had higher leptin (66.3 ± 34.2 vs. 35.7 ± 19.3 ng/mL, P < 0.001) compared to normal-weight women. Leptin was associated with total body fat (r = 0.782, P < 0.001) and resistin was associated with abdominal visceral fat (r = 0.452, P = 0.045). No significant correlations were observed between adiponectin or visfatin and any measure of body composition. In pregnant women, resistin has the potential to be a circulating biomarker for visceral fat, an ectopic fat compartment. These observational data may provide insight for the pathophysiological roles of adipokines and the impact of visceral fat in pregnant women.

Intrauterine DHA exposure and child body composition at 5 y: exploratory analysis of a randomized controlled trial of prenatal DHA supplementation

Background

Observational studies find associations between maternal docosahexaenoic acid (DHA) and greater fat-free mass and lower percentage of body fat, but randomized trials of prenatal DHA supplementation have not found significant intent-to-treat effects on childhood body composition.

Objective

This study sought to explore associations between intrauterine DHA exposure and body composition and size at 5 y in the offspring of women who participated in a randomized trial of prenatal DHA supplementation (corn and soybean oil placebo or 600 mg/d).

Design

At 5 y, body composition was measured by air displacement plethysmography in 154 offspring of women who had participated in the Kansas University DHA Outcomes Study and who had red blood cell (RBC) phospholipid (PL) fatty acids assessed at enrollment and delivery. We used linear regression models to analyze the relation among 3 indicators of intrauterine DHA exposure-1) intent-to-treat (placebo or DHA), 2) maternal RBC PL DHA status at delivery, and 3) change in maternal DHA (delivery minus enrollment)-and 6 outcomes of interest: 5-y fat mass, fat-free mass, percentage of body fat, height, weight, and body mass index z score.

Results

Change in maternal RBC PL DHA correlated with higher fat-free mass (r = 0.21, P = 0.0088); the association was unchanged after adjustment for maternal, perinatal, and childhood dietary factors. Intent-to-treat and DHA status at delivery showed positive trends with fat-free mass that were not statistically significant. There was no evidence relating intrauterine DHA exposure to any other body composition measure.

Conclusions

Change in maternal DHA status during pregnancy was related to higher offspring 5-y fat-free mass. The other 2 indicators of intrauterine exposure to DHA suggested a trend for higher offspring 5-y fat-free mass. Our findings agree with an earlier observational study from the United Kingdom. This trial was registered at clinicaltrials.gov as NCT00266825.

The effect of high dietary fiber intake on gestational weight gain, fat accrual, and postpartum weight retention: a randomized clinical trial

BACKGROUND

Interventions to prevent excessive gestational weight gain (GWG) have had limited success This pilot study examined the effectiveness of a single goal (SG) high dietary fiber intervention to prevent excessive GWG.

METHODS

Twelve weekly lessons focused on consuming a high fiber diet (≥30 g/day). Snacks containing 10-12 g of dietary fiber were given for the first 6 weeks only. Body composition was measured at baseline and at the end of the intervention. At one-year postpartum, body weight retention and dietary practices were assessed. A p-value is reported for the primary analysis only. For all other comparisons, Cohen's d is reported to indicate effect size.

RESULTS

The SG group increased fiber intake during the study (32 g/day at 6 weeks, 27 g/day at 12 weeks), whereas the UC group did not (~ 17 g/day). No differences were found for the proportion of women classified as excessive gainers (p = 0.13). During the intervention, the SG group gained less body weight (- 4.1 kg) and less fat mass (- 2.8 kg) (d = 1.3). At 1 year postpartum, the SG group retained less weight (0.35 vs. 4.4 kg, respectively, d = 1.8), and reported trying to currently eat high fiber foods.

CONCLUSION

The SG intervention resulted in less weight gain, fat accrual, and weight retention at 1 year postpartum. A residual intervention effect was detected postpartum with the participants reporting continued efforts to consume a high fiber diet.

TRIAL REGISTRATION

NCT03984630; Trial registered June 13, 2019 (retrospectively registered).

Association Between Added Sugars from Infant Formulas and Rapid Weight Gain in US Infants and Toddlers

BACKGROUND

Formulas often contain high amounts of added sugars, though little research has studied their connection to obesity.

OBJECTIVES

This study assessed the contribution of added sugars from formulas during complementary feeding on total added sugar intakes, and the association between these sugars and upward weight-for-age percentile (WFA%) crossing (i.e., participants crossing a higher threshold percentile were considered to have an upward crossing).

METHODS

Data from three 24-hour dietary recalls for infants (n = 97; 9-12 months) and toddlers (n = 44; 13-15 months) were obtained in this cross-sectional analysis. Foods and beverages with added sugars were divided into 17 categories. Pearson's correlations were used to test relations between added sugar intake and upward WFA% crossing, followed by multivariable regressions when significant. ANOVA compared intakes of all, milk-based, and table foods between primarily formula-fed compared with breastfed participants. Multivariable regressions were used to test effects of added sugars and protein from all foods compared with added sugars and protein from milk-based sources on upward WFA% crossing.

RESULTS

Added sugars from formulas comprised 66% and 7% of added sugars consumed daily by infants and toddlers, respectively. A significant association was observed between upward WFA% crossing and added sugars from milk-based sources after controlling for gestational age, sex, age, introduction to solid foods, mean energy intakes, and maternal pre-pregnancy BMI and education (β = 0.003; 95% CI, 0.000-0.007; P = 0.046). Primarily formula-fed participants consumed nearly twice the energy from added sugars (P = 0.003) and gained weight faster (upward WFA% crossing = 1.1 ± 1.2 compared with 0.3 ± 0.6, respectively; P < 0.001) than their breastfed counterparts.

CONCLUSIONS

Added sugars in formulas predict rapid weight gain in infants and toddlers. Educating mothers on lower-sugar options may enhance childhood obesity prevention.

Comparison of air displacement plethysmography to hydrostatic weighing for estimating total body density in children

BACKGROUND

The purpose of this study was to examine the accuracy of total body density and percent body fat (% fat) using air displacement plethysmography (ADP) and hydrostatic weighing (HW) in children.

METHODS

Sixty-six male and female subjects (40 males: 12.4 +/- 1.3 yrs, 47.4 +/- 14.8 kg, 155.4 +/- 11.9 cm, 19.3 +/- 4.1 kg/m2; 26 females: 12.0 +/- 1.9 yrs, 41.4 +/- 7.7 kg, 152.1 +/- 8.9 cm, 17.7 +/- 1.7 kg/m2) were tested using ADP and HW with ADP always preceding HW. Accuracy, precision, and bias were examined in ADP with HW serving as the criterion method. Lohman's equations that are child specific for age and gender were used to convert body density to % fat. Regression analysis determined the accuracy of ADP and potential bias between ADP and HW using Bland-Altman analysis.

RESULTS

For the entire group (Y = 0.835x + 0.171, R2 = 0.84, SEE = 0.007 g/cm3) and for the males (Y = 0.837x + 0.174, R2 = 0.90, SEE = 0.006 g/cm3) the regression between total body density by HW and by ADP significantly deviated from the line of identity. However in females, the regression between total body density by HW and ADP did not significantly deviate from the line of identity (Y = 0.750x + 0.258, R2 = 0.55, SEE = 0.008 g/cm3). The regression between % fat by HW and ADP for the group (Y = 0.84x + 3.81, R2 = 0.83, SEE = 3.35 % fat) and for the males (Y = 0.84x + 3.25, R2 = 0.90, SEE = 3.00 % fat) significantly deviated from the line of identity. However, in females the regression between % fat by HW and ADP did not significantly deviate from the line of identity (Y = 0.81x + 5.17, R2 = 0.56, SEE = 3.80 % fat). Bland-Altman analysis revealed no bias between HW total body density and ADP total body density for the entire group (R = 0.-22; P = 0.08) or for females (R = 0.02; P = 0.92), however bias existed in males (R = -0.37; P < or = 0.05). Bland-Altman analysis revealed no bias between HW and ADP % fat for the entire group (R = 0.21; P = 0.10) or in females (R = 0.10; P = 0.57), however bias was indicated for males by a significant correlation (R = 0.36; P < or = 0.05), with ADP underestimating % fat at lower fat values and overestimating at the higher % fat values.

CONCLUSION

A significant difference in total body density and % fat was observed between ADP and HW in children 10-15 years old with a potential gender difference being detected. Upon further investigation it was revealed that the study was inadequately powered, thus we recommend that larger studies that are appropriately powered be conducted to better understand this potential gender difference.

Intermittent and continuous energy restriction result in similar weight loss, weight loss maintenance, and body composition changes in a 6 month randomized pilot study

Poor adherence is a barrier to successful weight control. Intermittent energy restriction (IER) provides an alternative approach to those for whom daily energy restriction is not ideal. This study assessed changes in weight, body composition, and macronutrient intake for an IER and a continuous energy restriction (CONT) approach within a multicomponent weight management intervention. We randomized 35 adults with overweight/obesity (BMI = 31.2 ± 2.4 kg/m² ) to CONT or IER for 24 weeks (12-week weight loss intervention and 12 weeks of weight loss maintenance). Diets were delivered within a multimodal weight management program including weekly group meetings with a registered dietitian, increased physical activity, and a comprehensive lifestyle change program. Retention and adherence were similar for CONT and IER. Weight, BMI, fat mass, percentage body fat, waist circumference, hip circumference, blood pressure, and heart rate all decreased after 24 weeks (all, P < .01), but there were no main effects of group (all, P > .27). Weight loss was clinically relevant in both CONT (11.38 ± 7.9%) and IER (9.37 ± 9.7%), and the proportion of each group achieving 5% weight loss was 82 and 61% (P = .16), respectively. Participant satisfaction was high in both groups. The results from this study (a) support the feasibility of IER as an alternative for weight loss and weight loss maintenance, (b) indicate that IER is an effective alternative to CONT for weight control and improvements in body composition, and (c) emphasize the importance of intensive lifestyle interventions with ongoing support for effective behaviour modification.