Infant body composition: A comprehensive overview of assessment techniques, nutrition factors, and health outcomes.

Body composition assessment is a valuable tool for clinical assessment and research that has implications for long-term health. Unlike traditional measurements such as anthropometrics or body mass index, body composition assessments provide more accurate measures of body fatness and lean mass. Moreover, depending on the technique, they can offer insight into regional body composition, bone mineral density, and brown adipose tissue. Various methods of body composition assessment exist, including air displacement plethysmography, dual-energy x-ray absorptiometry, bioelectrical impedance, magnetic resonance imaging, D3 creatine, ultrasound, and skinfold thickness, each with its own strengths and limitations. In infants, several feeding practices and nutrition factors are associated with body composition outcomes, such as breast milk vs formula feeding, protein intake, breast milk composition, and postdischarge formulas for preterm infants. Longitudinal studies suggest that body composition in infancy predicts later body composition, obesity, and other cardiometabolic outcomes in childhood, making it a useful early marker of cardiometabolic health in both term and preterm infants. Emerging evidence also suggests that body composition during infancy predicts neurodevelopmental outcomes, particularly in preterm infants at high risk of neurodevelopmental impairment. The purpose of this narrative review is to provide clinicians and researchers with a comprehensive overview of body composition assessment techniques, summarize the links between specific nutrition practices and body composition in infancy, and describe the neurodevelopmental and cardiometabolic outcomes associated with body composition patterns in term and preterm infants.

Trends in Preterm Body Composition and Neurodevelopmental Outcomes after Discharge.

INTRODUCTION: Body composition, specifically fat-free mass (FFM), of preterm infants is associated with improved neurodevelopmental outcomes. Little is known about body composition of preterm infants after discharge. Preterm body composition was measured by air displacement plethysmography (ADP) at two time points, inpatient (35-40 weeks postmenstrual age [PMA]) and outpatient (48-58 weeks PMA), with neonatal factors and neurodevelopmental testing at 4-6 months corrected age. We hypothesized increased FFM is positively associated with neurodevelopment. METHODS: From 2007 to 2011, 510 infants admitted to the Medical University of South Carolina's neonatal intensive care unit underwent ADP. A total of 379 of 510 (74%) had anthropometrics at birth, an ADP scan with FFM, fat mass, fat percent z-scores, and an outpatient neurodevelopmental evaluation (CAT/CLAMS, Peabody Gross Motor). Variables were compared using multivariate analyses for body composition measurements. RESULTS: The infants were 32 ± 4.8 weeks gestational age at birth with an average birth weight of 1,697 ± 932 g. Most (56%) infants received maternal milk at discharge. CAT, CLAMS, and gross motor scores had positive correlations with FFM z-scores at inpatient and outpatient ADP (p < 0.05). Receiving maternal milk at discharge was positively associated with cognitive (ß = 0.22, p < 0.05) and language scores (ß = 0.26, p < 0.05). CONCLUSION: Increased FFM is associated with improved cognitive, language, and gross motor testing. Maternal milk was positively associated with language and cognitive scores.

Associations of Smoking, Cytomegalovirus Serostatus, and Natural Killer Cell Phenotypes in Smokers With and At Risk for COPD.

Introduction: Chronic obstructive disease (COPD) risk factors, smoking, and chronic infection (cytomegalovirus [CMV]) may mold natural killer (NK) cell populations. What is not known is the magnitude of the effect CMV seropositivity imparts on populations of smokers with and at risk for COPD. We investigate the independent influence of CMV seropositivity on NK cell populations and differential effects when stratifying by COPD and degree of smoking history. Methods: Descriptive statistics determine the relationship between cytotoxic NK cell populations and demographic and clinical variables. Multivariable linear regression and predictive modeling were performed to determine associations between positive CMV serology and proportions of CD57+ and natural killer group 2C (NKG2C)+ NK cells. We dichotomized our analysis by those with a heavy smoking history and COPD and described the effect size of CMV seropositivity on NK cell populations. Results: When controlled for age, race, sex, pack-years smoked, body mass index, and lung function, CMV+ serostatus was independently associated with a higher proportion of CD57+, NKG2C+, and NKG2C+CD57+ NK cells. CMV+ serostatus was the sole predictor of larger NKG2C+ and CD57+NKG2C+ populations. Associations are more pronounced in those with COPD and heavy smokers. Conclusions: Among Veterans who are current and former smokers, CMV+ serostatus was independently associated with larger CD57+ and NKG2C+ populations, with a larger effect in heavy smokers and those with COPD, and was the sole predictor for increased expression of NKG2C+ and CD57+NKG2C+ populations. These findings may be broadened to include the assessment of longitudinal NK cell population change, accrued inflammatory potential, and further identification of pro-inflammatory NK cell population clusters.

Body Composition and "Catch-Up" Fat Growth in Healthy Small for Gestational Age Preterm Infants and Neurodevelopmental Outcomes.

To examine the growth and body composition of small for gestational age (SGA) and appropriate for gestational age (AGA) very low birth weight infants (VLBW) and their outpatient neurodevelopmental outcomes. From 2006-2012, VLBW infants (n = 57 of 92) admitted to the Neonatal Intensive Care Unit (NICU) had serial air displacement plethysmography (ADP) scans and were followed as outpatients. Serial developmental testing (CAT/CLAMS, Peabody Gross Motor Scales) and anthropometrics were obtained from n = 37 infants (29 AGA and 8 SGA) and analyzed via repeated measures analyses of variances. The percentage of body fat, percentage of lean mass, and weight gain were statistically significant between SGA and AGA groups at the first ADP assessment. There was no difference between the two groups in outpatient neurodevelopmental testing. Weight gain as "catch-up" body fat accrual occurs by 67 weeks of PMA. This catch-up growth is associated with normal SGA preterm neurodevelopment as compared to AGA preterm infants.

Cytomegalovirus Seropositivity is Associated with Airflow Limitation in a Cohort of Veterans with a High Prevalence of Smoking.

BACKGROUND: Cytomegalovirus (CMV) represents an understudied chronic infection, usually contracted early in life, that causes chronic immune system alterations which may contribute to airflow limitations in a cohort of veterans with a high prevalence of smoking. We studied 172 participants at-risk for and with airflow limitation with available CMV serology to assess the relationship between CMV infection and chronic obstructive pulmonary disease (COPD)-related outcomes. METHODS: The study cohort includes 172 veterans who are smokers with or at risk for the development of COPD. Clinical data were obtained by chart abstraction at enrollment. CMV affinity (ever-exposure) and avidity testing (length of exposure) were performed on plasma samples collected at enrollment. Bivariable and multivariable logistic regression was used to determine the relationship between both cytomegalovirus affinity and avidity and odds of prevalent airflow limitation (post-bronchodilator forced expiratory volume in 1 second to forced vital capacity ratio <0.70) at enrollment. In those with airflow limitation (n=84), bivariable and multivariable logistic regression was used to determine relationships between CMV serostatus and reported exacerbations of COPD over 2 years prior to enrollment. RESULTS: Positive CMV serostatus was independently associated with a 136% higher odds of airflow limitation (95% confidence interval 1.11-5.06, P=0.03) at enrollment. Neither CMV affinity nor avidity was associated with COPD exacerbations in the 2 years prior to enrollment. CONCLUSIONS: CMV serostatus is independently associated with airflow limitation in a cohort of veterans who smoke. Investigation into the timing of infection and alterations in cellular immunity caused by chronic CMV infection and smoking-related airways disease-related outcomes is warranted.

Unique natural killer cell subpopulations are associated with exacerbation risk in chronic obstructive pulmonary disease.

Chronic Obstructive Pulmonary Disease (COPD) is the third leading cause of death worldwide. COPD is frequently punctuated by acute exacerbations that are precipitated primarily by infections, which increase both morbidity and mortality and inflates healthcare costs. Despite the significance of exacerbations, little understanding of immune function in COPD exacerbations exists. Natural killer (NK) cells are important effectors of innate and adaptive immune responses to pathogens and NK cell function is altered in smokers and COPD. Using high-dimensional flow cytometry, we phenotyped peripheral blood NK cells from never smokers, smokers, and COPD patients and employed a non-supervised clustering algorithm to define and detect changes in NK cell populations. We identified greater than 1,000 unique NK cell subpopulations across patient groups and describe 13 altered NK populations in patients who experienced prior exacerbations. Based upon cluster sizes and associated fluorescence data, we generated a logistic regression model to predict patients with a history of exacerbations with high sensitivity and specificity. Moreover, highly enriched NK cell subpopulations implicated in the regression model exhibited enhanced effector functions as defined by in vitro cytotoxicity assays. These novel data reflect the effects of smoking and disease on peripheral blood NK cell phenotypes, provide insight into the potential immune pathophysiology of COPD exacerbations, and indicate that NK cell phenotyping may be a useful and biologically relevant marker to predict COPD exacerbations.

Therapeutic paralysis in veterans with COPD.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is a common disorder of Veterans that causes significant morbidity and mortality. To measure Veterans' perceptions about COPD, the effect of COPD on their lives and health, and their needs for improved health, we performed a postal survey. METHODS: 3263 Veterans with a diagnosis of COPD who received care at the Cincinnati Veterans Affairs Medical Center in 2008 were stratified into quintiles by Veterans Health Administration-associated COPD healthcare cost and uniformly sampled. RESULTS: 493 of 1000 surveys (49%) were completed and returned. COPD had different effects on respondents in top and bottom quintiles (highest and lowest COPD-related cost) for: knowledge of COPD diagnosis (89% vs. 73%, p = 0.03); activities affected by breathing, including work (69% vs. 45%), recreation (85% vs. 62%), change in living arrangements (36% vs 16%), and increased need for help (54% vs. 25%) (p < 0.05 for all comparisons); emotional effect of respiratory symptoms, including depression (53% vs. 30%), fear (41% vs. 15%), and helplessness (49% vs. 24%) (p < 0.05 for all comparisons). 91% of Veterans were prescribed inhalers and one-quarter had difficulties using them. 25% of Veterans did nothing when they had symptoms of an exacerbation. CONCLUSIONS: COPD has profound effects on Veterans' breathing related activities and generates many negative emotions. Primary care providers are critical in conveying the diagnosis of COPD and providing information about the disease and its management. Veterans with COPD adhere poorly to their medications, and report little instruction about COPD or its management.

Patient reported determinants of health: a qualitative analysis of veterans with chronic obstructive pulmonary disease.

Although COPD is a common disorder of veterans who receive care from the Veterans Healthcare Administration (VHA), the perceptions of veterans with COPD about their disease, its effects on their lives, and their interactions with the VHA have not been determined. Utilizing qualitative methodology, we conducted focus groups of veterans with COPD at the Cincinnati VA Medical Center. Participants were selected by systematic sampling from the top quintile of veterans stratified by the cost of healthcare utilization related to a primary diagnosis of COPD and grouped by age and use of supplemental oxygen. All 42 participants were male and had a mean age of 65 years. Analysis of the focus group transcripts demonstrated five major themes: 1) Physical and Functional Limitations: work and employment constraints, recreation restrictions, limits on activities of daily living, reduced sexuality, concerns about housing and finances, and physical symptoms; 2) Restricted Social Interactions/Altered Social Networks: altered relationships with friends and family and reliance upon family and care givers; 3) Emotional Effects: reduced self-worth, vulnerability, depression, perseverance and adaptation, hopelessness, fear, pride, and lack of control; 4) Limitations in the Understanding of COPD: unawareness of diagnosis, triggers and reaction to disease manifestations, COPD management; and 5) Complex Healthcare Interactions. COPD pervasively and extensively affects all aspects of veterans' lives and causes significant consequences for their care and management.

Dynamic hyperinflation correlates with exertional oxygen desaturation in patients with chronic obstructive pulmonary disease.

BACKGROUND: Dynamic hyperinflation (DH) causes exercise limitation and exertional dyspnea in patients with chronic obstructive pulmonary disease (COPD). Exertional desaturation (ED) also occurs commonly in COPD but neither routine physiologic parameters nor imaging predict ED accurately. In this study we evaluated the relationship between DH and ED during 6-min walk testing (6MWT). METHODS: We measured ED and DH in patients with stable COPD. SpO2 was measured by continuous pulse oximetry during 6MWT. ED was defined as a decline in SpO2 (ΔSpO2) ≥4 %. DH was determined by measuring inspiratory capacity (IC) before and after the 6MWT using a handheld spirometer. DH was defined as ΔIC >0.0 L. We correlated DH and ED with clinical and pulmonary physiologic variables by regression analysis, χ (2), and receiver operator curve (ROC) analysis. RESULTS: Thirty males [age = 65 ± 9.4 years, FEV1 % predicted = 48 ± 14 %, and DLCO % predicted = 50 ± 21 % (mean ± SD)] were studied. ΔSpO2 correlated with ΔIC (r = 0.49, p = 0.005) and age (r = 0.39, p = 0.03) by univariate analysis; however, only ΔIC correlated on multivariate regression analysis (p = 0.01). ΔSpO2 did not correlate with FEV1, FVC, FEF25-75, RV, DLCO % predicted, BMI, smoking, BORG score, or distance covered in 6MWT. DH strongly correlated with ED (p = 0.001). On ROC analysis, DH had an area under the curve of 0.92 for the presence of ED (sensitivity = 90 %; specificity = 77 %, p < 0.001). CONCLUSION: Routine pulmonary function test results and clinical variables did not correlate with ED in patients with stable COPD. Dynamic hyperinflation strongly correlates with exertional desaturation and could be a reason for this desaturation.