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Background: The Shanghai growth standards are higher than World Health Organization (WHO) growth standards, which may influence the feeding practices of the caregivers and increase the risk of overweight in these infants. This study aimed to compare the effects of different growth standards on childhood obesity in Shanghai metropolitan area. Methods: This was a cluster-randomized controlled trial conducted in 2 downtown areas with 19 community health service centers in Shanghai from November 2013 to December 2015. Randomization was done at the level of the community. Infants (health newborns) were assessed and monitored by the Shanghai growth standards (S-group) and the 2006 WHO growth standards (W-group), respectively. Measurements were taken at 1.0, 2.0, 4.0, 6.0, 9.0 and 12.0 months of age during follow-up period. Based on the values of length and weight measurements, according to the group’s growth standards, doctors provided the caregivers with corresponding clinical consultation. Changes in weight-for-age z-score (WAZ), length-for-age z-score (LAZ), and weight-for length z-score (WLZ) between 2 groups were assessed using mixed regression models. Overweight was compared between 2 group at all follow-up measurements. Results: A total of 6509 infants (52.1% were boys) were in the W-group, and 8510 infants (51.4% were boys) were in the S-group. The overweight ratios between two groups were distinct at 9 months of age (3.4% in W-group and 4.3% in S-group) and 12 months of age (2.2% in W-group and 3.8% in S-group), and the differences were statistically significant (P= 0.020 and P< 0.001, respectively). Compared to W-group, the increase in WAZ (coefficient= 0.04, P= 0.004) and WLZ (coefficient= 0.09, P < 0.001) were significantly greater, and the LAZ was lower (coefficient = －0.04, P = 0.047) in S-group (W-group values were used as reference in mixed regression models). Conclusion: Compared to the Shanghai growth standards, the adoption of WHO 2006 growth standards would reduce the risk of infant overweight in Shanghai metropolitan area up to 1 year of age. Trial registration number: ChiCTR1800015371, http://www.chictr.org.cn/Chinese Clinical Trial Registry. Key words: Overweight; community health; infant; growth standards

OBJECTIVE: To establish a food allergy model in Brown Norway (BN) rats by gavage of ovalbumin (OVA) without any adjuvant, and to evaluate this model. METHODS: A total of 20 male BN rats aged 3 weeks were randomly divided into allergy group and control group (n=10 each). BN rats in the allergy group were given OVA 1 mg per day by gavage, and all the rats were treated for 41 days continuously. On day 42, the rats in the allergy group were given OVA 100 mg by gavage for challenge. The rats in the control group were given normal saline of the same volume by gavage. Differences in body length, body weight, and food intake were compared between the two groups on days 7, 14, 21, 28, 35, and 42. ELISA was used to measure the serum OVA-IgE level and plasma histamine level after challenge on day 42, and the changes in rats' appearance and fecal properties were observed. The model of food allergy was considered successful when the serum OVA-IgE level in the allergy group was no less than the mean serum OVA-IgE level + 3 standard deviation in the control group. RESULTS: There were no significant differences in body length, body weight or food intake between the allergy and control groups at all time points (P > 0.05). On day 21, the control group had a significantly higher food intake than the allergy group (P < 0.05). On day 42 after challenge, the allergy group showed significantly higher serum OVA-IgE and plasma histamine levels than the control group (P < 0.05). The sensitization rate (rate of successful modeling) was 90%. The fecal properties showed no significant differences between the two groups. CONCLUSIONS: OVA by gavage without any adjuvant can successfully establish the model of food allergy in BN rats and has a high success rate. Food allergy induced by OVA may reduce food intake within a short period of time, but no influence on rats' body length or body weight has been observed.

Faltering linear growth is commonly encountered in children with intestinal inflammation. Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) are important regulators of postnatal longitudinal bone growth. Inhibition of GH/IGF axis will result in growth failure in young children. Pro-inflammatory cytokines such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) abnormally increase in children with intestinal inflammation, and may affect linear growth both systemically and locally at the level of the growth plate though disturbing the GH/IGF axis.