The association between environmental exposures and the physical growth status, bone growth status, and metabolic risk factors of children of Sudanese immigrant families living in the USA.

摘要

Objectives The purpose of this research was to describe the physical growth status, bone mineral content, areal bone mineral density, body composition, and metabolic risk level of children of Sudanese immigrant families, and to determine the relationship between these outcome measures and exposure to an adverse environment. Exposure was defined as the time spent in Sudan or neighboring countries and timing was defined as the age a child arrived in the USA. Two major modifying factors were considered; current nutritional status (food quality and food security) and current physical activity levels.;Study Design and Methods This is a cross-sectional study conducted between July 2011 and April 2012. Subjects were recruited from the Iowa City, Iowa metropolitan area. The sample included 64 children between the ages of five and eighteen; 33 females and 31 males. Physical growth measures included weight, height, and BMI. Bone growth measures (body bone mineral content and areal bone mass density at the hip and spine) and body composition measures (lean mass, fat mass, and body fat percent) were measured using DXA. Metabolic risk factors included fasting blood glucose, low density lipoprotein (LDL), high density lipoprotein (HDL), total cholesterol, triglyceride, and C Reactive Protein (CRP) levels, and Homeostasis Model of Assessment Insulin Resistance (HOMA-IR). Physical activity was measured by self-report physical activity questionnaire for children and adolescents (modified PAQ-A and PAQ-C) and by direct measure using Omron Pedometers (HJ-720 IT). Other collected data included food quality, food security, food frequency, and pubertal development using a puberty developmental scale.;Results The mean age for all children was 10.1 +/- 3.3 years. More than half of the children (n=33, 51.6%) were born in the USA, 14 children (21.9%) were born in Sudan, and the other children were born in other countries. The majority of the children (63.6%) lived in low income households reporting annual income less than USD ;The mean Z score for FMI and LMI were -0.57 +/- 1.51 and 0.49 +/- 0.75, respectively, and neither was normally distributed. Around half of the children had FMIZ (53.1%) and LMIZ (47%) scores more than 1 SD below the mean. Median Z scores for all bone measures were negative; BMC, -0.71, hip aBMD, -0.53, and Spine aBMD, -0.13. Around one-third of the children fell more than 1sd below the mean for BMC (38%) and hip aBMD (33%). Metabolic risk factors were elevated in some subjects; high total cholesterol, 23.4%; high triglycerides, 32.8%; low HDL, 19%; high HOMA-IR and CRP levels, 15.6 %.;Using GEE analysis, longer residence in Sudan was associated with lower WAZ scores (beta =-0.16, p= 0.07), and lower LMIZ scores (beta =-0.05, p= 0.06). Children with longer residence in Sudan or neighboring countries had higher LDL and HOMA-IR levels (beta =2.997, p= 0.0005), and (beta =0.03, p= 0.08). Adjusting for gender, girls who spent more time in Sudan had higher triglyceride and CRP levels beta =11.9, p=0.027) and (beta =0.5, p=0.03), respectively.;Children who were older when they entered the USA had higher HAZ scores (beta =0.06, p=0.05). Adjusting for gender, Girls who arrived in the USA at a younger age had lower WAZ scores (beta =-0.42, p=0.01), while girls who entered the USA at an older age had higher HOMA-IR, triglyceride, and CRP levels (beta =0.29, p=0.005), (beta =0.14, p= 0.05) and (beta =0.5, p=0.05), respectively.;Adjusting for number of years spent in the USA and physical activity levels, longer residence in Sudan was associated with poorer LMIZ (beta =-0.06, p=0.001) and hip aBMD Z scores (beta =0.11, p= 0.01). In addition, children who arrived in the USA at a younger age had higher height for age Z scores (beta=0.094, p=0.005) and lower LMIZ scores (beta =-0.09, p=0.04), respectively.;Conclusion Sudanese children in the Iowa City metropolitan area, particularly those born in the USA, have low Z scores for physical growth, bone growth, and body composition measures. A significant percent of the children had high triglycerides and total cholesterol levels. The majority of Sudanese children were physically inactive and food insecurity was common. (Abstract shortened by UMI.).