Summary: Childhood obesity increases the risk of adulthood obesity and is associated with other adverse health outcomes later in life. It may be influenced by environmental characteristics of neighborhoods where children live, particularly dietary supply–related environmental factors. This study aimed to systematically review the evidence on the association between access to convenience stores and childhood obesity. We searched and filtered relevant literature in PubMed, Embase, Web of Science, and Cochrane Library published before 1 January 2019. Data on the basic characteristics of studies, measures of access to convenience stores, and associations of convenience stores with weight‐related behaviors and outcomes were extracted from 41 included studies. In general, the density of and proximity to convenience stores in children's residential and school neighborhoods were positively associated with unhealthy eating behaviors. However, their associations with children's weight status varied significantly by regions. The association between convenience store access and children's weight status was found to be negative in Canada, rather mixed in the United States and the United Kingdom, and not significant in East Asia. We suggest future research to clearly define the convenience store, better measure the access to convenience store, and also measure children's journey and food purchasing and consumption behaviors, to explain pathways from convenience store access to childhood obesity for designing effective interventions and policies.

Summary: A growing body of research links traffic‐related environmental factors to childhood obesity; however, the evidence is still inconclusive. This review aims to fill this important research gap by systematically reviewing existing research on the relationship between traffic‐related environmental factors and childhood obesity. Based on the inclusion criteria, 39 studies are selected with environmental factors of interest, including traffic flow, traffic pollution, traffic noise, and traffic safety. Weight‐related behaviours include active travel/transport, physical activity (PA), and intake of a high trans‐fat diet or stress symptoms; weight‐related outcomes are mainly body mass index (BMI) or BMI z‐scores and overweight/obesity. Of 16 studies of weight‐related behaviours, significant associations are reported in 11 out of 12 studies on traffic flow (two positively and nine negatively associated with PA), five out of six studies on traffic safety (four positively and one negatively associated with PA), one study on traffic pollution (positively with unhealthy food consumption), and one study on traffic noise (negatively associated with PA). Among 23 studies of weight‐related outcomes, significant associations are reported in six out of 14 studies on traffic flow (five positively and one negatively associated with obesity outcome), seven out of 10 studies on traffic pollution (all positively associated with obesity outcome), and two out of five on traffic noise (all positively associated with obesity outcome). Our findings show that long‐term traffic pollution is weakly positively associated with children's BMI growth, and traffic flow, pollution, and noise could affect weight‐related behaviours. Associations between traffic density and noise and weight status are rather inconclusive.

Summary: Childhood obesity is one of the most pressing public health issues nowadays. The environmental factors have been identified as potential risks for obesity, as they may influence people's lifestyle behaviours. Lack of access to supermarkets that usually provide healthy food options has been found to be a risk factor for childhood obesity in several studies. However, findings remained inconclusive. We aimed to systematically review the association between access to supermarkets and childhood obesity. A literature search was conducted in the Cochrane Library, PubMed, Web of Science, and Embase for studies published before 1 January 2019. Twenty‐four studies conducted in four countries were identified, from which data on the basic characteristics of studies and participants, measures of access to supermarkets, and associations between access to supermarkets and weight‐related behaviours and outcomes were extracted. The median sample size was 1858 participants. Half of the included studies indicated a negative association, one fourth reported a positive association, and the remaining one fourth did not find a significant association. Better designed studies are necessary to achieve a robust understanding of this epidemiological relationship in the future.

Summary: The lack of bike lane access has been a proven risk factor for childhood obesity due to its role in discouraging healthy lifestyles. However, there has not been a systematic review of this important association in the existing literature. This study aims to fill this gap. A literature search was conducted in the Cochrane Library, PubMed, Embase, and Web of Science for studies published from 1 January 2019 onwards that examined the association between bike lane access and weight‐related behaviours and outcomes among children aged <18 years. A total of 21 studies were included in this systematic review. Among them, most of the studies showed that bike lane access was significantly associated with children and adolescents' physical activity (PA), whereas only two studies showed a negative association. Meta‐analysis also supported these findings and showed that bike lane access was significantly associated with children and adolescents' PA (odds ratio [OR] = 1.57, 95% confidence interval [CI]: 1.37–1.81). Additionally, we reviewed how bike lane characteristics and microenvironment variables such as children and adolescents' choice of bicycle travel mode, the degree of separation of cycle path, cycle path unevenness, and street maintenance were associated with adolescents' preferences and intention to cycle. This systematic review and meta‐analysis strongly suggests that bike lane access is associated with children and adolescents' PA. Nonetheless, it was difficult to draw a conclusion on the association between bike lane access and weight‐related outcomes.