Christina G. Campbell

Predicted vs measured energy expenditure in critically ill, underweight patients

A retrospective analysis was conducted to compare 4 energy-prediction equations against measured resting energy expenditure (MREE) determined via indirect calorimetry. Data from a heterogeneous group of 42 critically ill, severely underweight (59.50 +/- 17.30 kg; 77.1 +/- 9.7% ideal body weight [IBW]) male patients were assessed. The Hamwi formula was used to determine IBW. The Harris-Benedict (HB) equation was calculated for patients <90% IBW using both current body weight (CBW) and IBW. Energy needs were also estimated with an Ireton-Jones formula for all mechanically ventilated patients (n = 37). For patients <85% IBW (n = 31), an adjusted body weight was determined ([CBW + IBW]/2) and used in the HB formula. The HB formula using the IBW, CBW, and adjusted body weight was significantly different (p < .05) than MREE. The Ireton-Jones equation was not significantly different (p > .05) from MREE but tended to overestimate energy needs (109.3% +/- 16.8% MREE). Conversely, using the CBW or IBW in the HB underestimated the patients energy needs; 77.0% +/- 11.6% MREE and 90.9 +/- 16.1% MREE, respectively. For patients <85% IBW, use of the adjusted body weight in the HB represented 84.2% +/- 13.9% MREE. The average caloric need was 31.2 +/- 6.0 kcal/kg CBW. Indirect calorimetry remains the best method of determining a patients energy needs. Until a large prospective trial is conducted, a combination of prediction equations tempered with clinical judgment and monitoring the appropriateness of the nutrition prescription remains the best approach to quality patient care.

Position of the Academy of Nutrition and Dietetics: Nutrition and Lifestyle for a Healthy Pregnancy Outcome

It is the position of the Academy of Nutrition and Dietetics that women of childbearing age should adopt a lifestyle optimizing health and reducing risk of birth defects, suboptimal fetal development, and chronic health problems in both mother and child. Components leading to a healthy pregnancy outcome include healthy prepregnancy weight, appropriate weight gain and physical activity during pregnancy, consumption of a wide variety of foods, appropriate vitamin and mineral supplementation, avoidance of alcohol and other harmful substances, and safe food handling. Pregnancy is a critical period during which maternal nutrition and lifestyle choices are major influences on mother and child health. Inadequate levels of key nutrients during crucial periods of fetal development may lead to reprogramming within fetal tissues, predisposing the infant to chronic conditions in later life. Improving the well-being of mothers, infants, and children is key to the health of the next generation. This position paper and the accompanying practice paper (www.eatright.org/members/practicepapers) on the same topic provide registered dietitian nutritionists and dietetic technicians, registered; other professional associations; government agencies; industry; and the public with the Academys stance on factors determined to influence healthy pregnancy, as well as an overview of best practices in nutrition and healthy lifestyles during pregnancy.

Validity of the SenseWear® Armband to predict energy expenditure in pregnant women.

UNLABELLED Few valid, objective methods exist to quantify physical activity and predict energy expenditure (EE) during pregnancy. PURPOSE The purpose of this study was to evaluate the validity of the SenseWear Mini armband monitor (SWA) (BodyMedia, Pittsburgh, PA) to estimate EE in pregnant women. METHODS Thirty healthy pregnant women (22-24 wk of gestation) completed a series of activities of daily living (typing, laundry, sweeping, and treadmill walking: 2.0, 2.5, 3.0, and 3.0 mph, 3% incline) while EE was estimated by the SWA and measured by indirect calorimetry (IC). The SWA data were processed using both the v2.2 algorithm and the newer v5.2 algorithm. The estimated EE values were compared with the measured EE values using a three-way (method × algorithm × activity) mixed model ANOVA. Least square means ± SE were estimated in the model. Significance was set at P < 0.05. RESULTS The analyses revealed a significant method (IC vs. SWA) × algorithm (v5.2 vs. v2.2) interaction with significantly smaller error (IC-SWA) for the newer v5.2 algorithm (-0.57 ± 0.06 kcal.min(-1)) than the older v2.2 algorithm (-0.78 ± 0.06 kcal.min(-1)). The SWA significantly overestimated EE for all activities, except inclined walking. The average mean absolute percentage error was considerably lower for the new algorithm (22%) than that for the older algorithm (35%). The average individual correlation coefficients revealed good overall agreement between the SWA and the IC (v5.2, mean r = 0.93; v2.2, mean r = 0.87). CONCLUSION Overall, the SWA correlated well with IC; however, EE was significantly overestimated during most activities. Future studies should develop pregnancy-specific algorithms and assess validity of the SWA at all stages of pregnancy to further improve prediction of EE in this population.

Day-to-day variation in plasma interleukin-6 concentrations in older adults

Interleukin-6 (IL-6) is a pro-inflammatory cytokine commonly used in studies as a means of assessing chronic inflammatory status. Despite the use of plasma IL-6 as a marker of chronic inflammation few studies exist that examine the variability of plasma IL-6 within and between individuals. The purpose of this study was to assess inter- and intra-variability of plasma IL-6 concentration in men and postmenopausal women. Sixteen healthy postmenopausal women and 5 men completed the 2-week study. Fasted venous blood samples were obtained on three consecutive mornings for two consecutive weeks (six blood draws per participant). Mean plasma IL-6 values were 2.00+/-1.74 pg/mL. Intra-variability was not significantly different (p>0.05) however inter-variability was significantly different (p<0.05). The index of individuality (II) was 0.20 and the standard error of the mean (SEM) was determined to equal 0.16 pg/mL (0.32 pg/mL; 1.96 SEM). An II of 0.20 demonstrates the need to carefully evaluate changes in plasma IL-6 concentration instead of utilizing population-based reference norms. In an older adult population until plasma IL-6 differences exceed 0.32 pg/mL such values could be considered normal fluctuation between trials and most likely not attributable to a nutrition intervention.

Adherence to physical activity guidelines in mid-pregnancy does not reduce sedentary time: an observational study

BackgroundPhysical activity (PA) interventions designed to prevent prenatal complications have focused on increasing moderate PA yielding conflicting results. Minimal attention has focused on the evaluation of sleep, sedentary behavior (SB), light activity or total daily PA during pregnancy. The purpose of this prospective, longitudinal study was to 1) objectively quantify and compare habitual PA and SB during the 2nd and 3rd trimester; and 2) evaluate differences in activity patterns for women meeting prenatal PA guidelines versus those that did not.MethodsForty-six participants wore 2 PA monitors (SenseWear® Mini and activPAL™) during week 18 and week 35 of pregnancy. We compared differences in sleep duration, postural allocation, daily steps, and PA between the 2nd and 3rd trimester and for women who met and did not meet PA guidelines.ResultsDuring the 2nd trimester, 30% of the women’s day (24-hours) was total sleep; 52% SB; 13% light; 3% moderate; and 0% vigorous PA. Light (P = 0.05), vigorous (P = 0.02), and moderate-vigorous PA (MET-minutes; P = 0.02), decreased with a trend in increased SB (P = 0.07). Activity of other intensities and sleep duration did not significantly change. Only 39% and 37% of participants slept between 7–9 hours/night at week 18 and 35, respectively. Forty-six percent (n = 21) and 28% (n = 13) of participants met prenatal PA guidelines during the 2nd and 3rd trimester, respectively. At week 18, no differences in total sleep, SB, or light PA existed for women who met PA guidelines versus those who did not; total PA was significantly greater for women who met guidelines. At week 35, women that met PA guidelines had significantly less SB (P < 0.005) than women who did not.ConclusionsThis study demonstrates that pregnant women spend the majority of their day in SB. Significant reductions in total activity across pregnancy may be attributed, in part to shifts in light PA and increased SB. Based on the lifestyle of our sample, regardless of meeting PA guidelines in mid-pregnancy, no significant difference exists in time spent in SB, however meeting PA recommendations in late pregnancy may reduce SB. Future interventions should target reducing SB by increasing light and moderate PA beyond volitional exercise.

Accuracy of physical activity assessment during pregnancy: an observational study

BackgroundPrenatal physical activity may improve maternal and infant health and lower future disease risk for both mother and baby; however, very few physical activity assessment methods have been validated for use during pregnancy. The purpose of this study was to evaluate the accuracy of a subjective physical activity record (PAR) and an objective activity monitor, against a reference standard to quantify moderate and vigorous physical activity (MVPA) in pregnant women. The reference standard was based on participant interviews to determine if a woman was an exerciser and confirmed with information obtained from the PAR and a heart rate monitor.MethodsFifty-two pregnant women completed a physical activity record (PAR) and wore a SenseWear® Mini Armband (SWA) activity monitor over a 7-day period at 18 weeks gestation. Total minutes spent in MVPA were totaled from both modalities and evaluated against the reference standard using contingency analysis and Pearsons chi-square test to evaluate the number of women meeting minimum prenatal physical activity recommendations (at least 3, 30 minute sessions of exercise per week). Both modalities were also tested individually and collectively to assess their ability as indicators of activity using empirically determined cut-offs as indicated by receiver-operator characteristic curves. These experimentally-derived criteria were also tested with Pearsons chi-square test.ResultsAccording to the reference standard, 13 of 52 participants (25%) met the criterion of 3, 30 minute sessions of volitional, moderate-intensity activity. When compared to the reference standard, both the PAR and SWA overestimated exercise status; 42 (81%) and 52 (100%) participants, respectively, achieved 90 minutes of MVPA (P < 0.0001 for both comparisons). Single-modality predictors of MVPA did not show a significant correlation. A composite predictor of MVPA offered the most favorable option for sensitivity and specificity (true positives, n = 8 and true negatives, n = 36) using cut-offs of 280 and 385 minutes/week for the PAR and SWA, respectively.ConclusionCompared to the reference standard, time spent in MVPA obtained from the PAR or SWA overestimated the prevalence of women meeting prenatal exercise recommendations. The most accurate predictor of women meeting current prenatal exercise guidelines was identified by using the PAR and SWA collectively.

Academy of Nutrition and Dietetics 2011 Survey on Member Research Activities, Needs, and Perceptions

R ESEARCH RESULTING IN evidence-based recommendations is the foundation of nutrition and dietetics practice. The Academy of Nutrition and Dietetics (the Academy) conducted surveys of active members who are registered dietitians (RDs) with a doctorate and members of the Research Dietetic Practice Group (RDPG) in 2000, 2002, and 2006. In 2011, the Academy (then the American Dietetic Association) conducted another survey of members with a doctorate and members of the RDPG with a post-baccalaureate degree (ie, master’s degree or doctorate). The main objective of the 2011 Researcher Survey was to better understand member participation in research, defined as preparing applications/proposals, designing and conducting studies, preparing manuscripts for publication, and presenting at professional meetings, as well as supervising any of these activities. The survey also included questions about funding and the degree to which the RDs’ research interests correlated to Academy research priorities. The primary aim of this article is to summarize findings from the 2011 survey and discuss implications related to research among RDs.

Impact of a walking intervention during pregnancy on post-partum weight retention and infant anthropometric outcomes.

Few studies have investigated the impact of lifestyle interventions during pregnancy on post-partum weight retention and infant growth. Thirty seven previously non-exercising, overweight or obese pregnant women were randomly assigned to a walking intervention or non-intervention control. For the follow-up study, weight of the mother and weight, length and body composition of the infant were collected at 1 month post-partum (n=37) and 6 months post-partum (n=33). Analysis of variance and linear regression were conducted to determine the differences and association in maternal post-partum weight retention and child outcomes. At 6 months post-partum, weight retention of obese women in the intervention group (Int-OB) was -0.10±8.11 kg; while, obese women in the control group (Con-OB) was 6.35±7.47 kg. A significantly higher percentage of Con-OB women retained more than 5 kg at 6 months post-partum (P=0.046). Even though statistically non-significant between the groups, the growth trend observed among offspring of obese women in the control group was consistently higher than the offspring of obese women in the intervention group from birth to 6-months. Third trimester gestational weight gain rate significantly predicted 6-m weight-for-length z-score after controlling for birth weight, treatment group and pre-pregnancy body mass index (r 2=0.31, β=1.75, P=0.03). The reduced post-partum weight retention observed among the obese women in the intervention group may be explained in part by the lifestyle modification during pregnancy.

Physical activity during pregnancy: impact of applying different physical activity guidelines.

Multiple guidelines and definitions of physical activity (PA) have been used to study the benefits of activity during pregnancy. The different guidelines lead to a wide range of prevalence estimates and this has led to conflicting reports about activity patterns during pregnancy. A longitudinal study was conducted to assess PA using a pattern-recognition monitor for a 7-day period at week 18 (n = 55) and week 35 (n = 66) of pregnancy. The amount of activity performed and the number of women meeting six different PA guidelines were evaluated. Adherence to PA guidelines ranged from 5 to 100% and 9 to 100% at weeks 18 and 35, respectively. All women achieved the 500 MET-minute guideline and nearly all women accumulated ≥150 minutes of weekly moderate-vigorous physical activity (MVPA) at both time points. Only 22% and 26% participated in ≥3 sessions of MVPA lasting ≥30 minutes at both time points and this further declined to 5% and 9% when the guideline was increased to ≥5 sessions of 30 minutes. The amount of PA during pregnancy varied drastically depending on which guideline was used. Further research is warranted to clearly identify the patterns of activity that are associated with healthy pregnancy outcomes.

Web-Based Behavioral Intervention Increases Maternal Exercise but Does Not Prevent Excessive Gestational Weight Gain in Previously Sedentary Women

BACKGROUND Innovative methods are warranted to optimize prenatal outcomes. This studys objective was to determine if a web-based behavioral intervention (BI) can prevent excessive gestational weight gain (GWG) by increasing physical activity (PA). METHODS Participants were randomized to usual care (UC; n = 21) or BI (n = 24) between 10 to 14 weeks gestation. GWG, PA, and diet were assessed at baseline, mid-, and late pregnancy. RESULTS No differences in GWG or adherence to GWG recommendations presented between groups. Total UC MET-minutes significantly decreased from baseline to late-pregnancy (1,234 ± 372 MET-minutes, P = .013). Mid-pregnancy sustained PA was greater for BI than UC (20-minute PA bouts: 122 ± 106 vs. 46 ± 48 minutes/week, P = .005; 30-minute PA bouts: 74 ± 70 vs. 14 ± 24 minutes/week, P < .001), and greater for BI at mid-pregnancy compared with baseline (20-minute PA bouts: 61.3 ± 21.9; 30-minute PA bouts: 39.6 ± 14.8, both P < .05). BI energy intake at mid-pregnancy significantly increased from baseline (336 ± 127 kcals, P = .04) and was significantly greater than UC (2,503 ± 703 vs. 1,894 ± 594, P = .005). CONCLUSIONS Sedentary pregnant women should increase PA but may need additional dietary counseling to prevent excessive GWG.