Rapid BMI Increases and Persistent Obesity in Small-for-Gestational-Age Infants

Dan Wu; Jianzheng Zhu; Xiulian Wang; Huiqing Shi; Yanyan Huo; Meiyan Liu; Fanfan Sun; Hongyan Lan; Chong Guo; Honghua Liu; Tingting Li; Lian Jiang; Xiangying Hu; Tianshu Li; Jing Xu; Guoying Yao; Guowei Zhu; Guangjun Yu; Jinjin Chen

doi:10.3389/fped.2021.625853

Rapid BMI Increases and Persistent Obesity in Small-for-Gestational-Age Infants

Front Pediatr. 2021 May 4:9:625853. doi: 10.3389/fped.2021.625853. eCollection 2021.

Authors

Dan Wu¹, Jianzheng Zhu², Xiulian Wang¹, Huiqing Shi¹, Yanyan Huo¹, Meiyan Liu¹, Fanfan Sun¹, Hongyan Lan¹, Chong Guo³, Honghua Liu¹, Tingting Li¹, Lian Jiang¹, Xiangying Hu⁴, Tianshu Li⁵, Jing Xu⁶, Guoying Yao¹, Guowei Zhu⁷, Guangjun Yu¹, Jinjin Chen¹

Affiliations

¹ Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.
² School of International and Public Affairs, Shanghai Jiao Tong University, Shanghai, China.
³ Fujian Maternal and Child Health Hospital, Fujian, China.
⁴ Jing'an District Maternal and Child Healthcare Center, Shanghai, China.
⁵ Huang'pu District Maternal and Child Healthcare Center, Shanghai, China.
⁶ Yang'pu District Maternal and Child Healthcare Center, Shanghai, China.
⁷ Xu'hui District Maternal and Child Healthcare Center, Shanghai, China.

Abstract

Purpose: In order to compensate for the early intrauterine growth restriction, small-for-gestational age (SGA) infants have "catch-up growth" after birth. Increased caloric intake has been suggested for SGA infants conventionally. It is important to determine if the early growth rate of body mass index (BMI) is associated with risk of persistent obesity later in life. In this longitudinal cohort study, we assessed the BMI of a large cohort of children who were SGA at birth to determine their risk of persistent obesity at school age (6-7 years) due to excessive weight gain in the first 3 years of life. Methods: We collected the height and weight data of 23,871 SGA babies. A polynomial function was used to fit the BMI-for-age z-score (BAZ) values of 0-6 years old SGA children and interpolate their growth trajectory. In addition, we screened out 6,959 children from 23,871 children to further evaluate the dynamic changes of early childhood BMI. We divided the school-age children into groups as non-obese (BAZ < 2) and obese (BAZ > 2), and determined the association between changes in BMI and school-age obesity. Results: From the perspective of BMI distribution, the interpolated growth trajectory indicated that SGA children reaching overweight status or developing obesity by 3 years of age, continued to have obesity until school age (R², 0.65; R², 0.21). The retrospective analysis showed that children who were overweight and had obesity during school age had a high BMI from early age. By analyzing the changes in early BMI, we found that the fastest growth of SGA children occurred in the early infancy before 6 months and they continued to grow rapidly for a period of time. Interestingly, former SGA children who maintained a near overweight (1 < BAZ < 2) status before the age of 2 maintained an appropriate growth rate and usually did not develop obesity. Conclusions: A rapid increase in BMI during early infancy in former SGA newborns leads to a persistent risk of obesity. The energy intake of SGA infants should appropriately meet the infants' growth needs and early BMI changes should be closely monitored for an optimal integrated management.

Keywords: BMI changes; SGA; obesity; overweight; pediatric.