Background

Early childhood overweight and obesity increased substantially in high-income countries throughout the 1980s and 1990s. The flattening or reversal of this trend since the early 2000s might conceal widening inequalities. This study aimed to identify trends in body-mass index Z score (BMIz) among children aged 1–3·5 years in Victoria (Australia), by socioeconomic status and geographical location.

Methods

This repeated, cross-sectional study used deidentified records of height, weight, and demographic information from electronic databases in the Victorian Maternal and Child Health system. Data from the consultations for children aged 1, 2, and 3·5 years were included in this analysis. We removed duplicate records; records with missing data for sex, age, weight, height, or postcode; and records with postcodes that were outside of Victoria. The coprimary outcomes were trends in mean BMIz (continuous linear models) and prevalence of high BMIz (>+1; generalised linear models), estimated for six independent age–sex groups. Secondary analysis was done for the prevalence of BMIz greater than 2. Effect modification by socioeconomic status and remoteness was evaluated.

Findings

Electronic data were available for 48 local government areas collected between Jan 1, 2003, and Dec 31, 2017, representing approximately 63% of the Victorian population. Overall, 1 329 520 measurements from 675 991 children were included in the analysis. There were small, significantly decreasing trends in mean BMIz across all six age–sex groups, overall and in major cities. Similar patterns were observed for some subgroups in prevalence of high BMIz. These decreasing trends appear to be partly explained by migration. Conversely, in regional areas the trends in BMIz were consistently increasing in all age–sex groups and across socioeconomic strata, although not all groups were statistically significant. Inequalities in BMIz according to socioeconomic status persisted throughout the study period, such that the children from more advantaged areas had lower mean BMIz.

Interpretation

This study showed that at a state level, mean BMIz and prevalence of high BMIz decreased in children aged 1, 2, and 3·5 years in Victoria between 2003 and 2017. We found metropolitan–regional differences to be key source of inequality in early childhood BMIz trends, alongside area-level socioeconomic status. These findings highlight the risk that analysis of overall trends in childhood BMIz might obscure important inequalities according to, for example, remoteness, socioeconomic status, and ethnicity. Future research requires monitoring data with large population samples to adequately examine differences in prevalence and trends between population subgroups.

Funding

None.

中文翻译：

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澳大利亚维多利亚州幼儿体重指数 Z 分数的不平等：一项为期 15 年的观察性研究

背景

在整个 80 年代和 1990 年代，高收入国家的幼儿超重和肥胖大幅增加。自 2000 年代初以来这一趋势趋于平缓或逆转可能掩盖了不平等的扩大。本研究旨在根据社会经济地位和地理位置确定维多利亚州（澳大利亚）1-3·5 岁儿童的体重指数 Z 评分 (BMIz) 趋势。

方法

这项重复的横断面研究使用了来自维多利亚州妇幼保健系统电子数据库的身高、体重和人口统计信息的未识别记录。该分析包括 1、2 和 3·5 岁儿童的咨询数据。我们删除了重复的记录；缺少性别、年龄、体重、身高或邮政编码数据的记录；以及邮政编码在维多利亚州以外的记录。共同主要结果是平均 BMIz（连续线性模型）和高 BMIz 流行率（>+1；广义线性模型）的趋势，估计为六个独立的年龄-性别组。对 BMIz 大于 2 的流行率进行二次分析。评估了社会经济地位和偏远地区的影响。

发现

2003 年 1 月 1 日至 2017 年 12 月 31 日期间收集的 48 个地方政府区域的电子数据可用，约占维多利亚州人口的 63%。总体而言，分析中包括了来自 675 991 名儿童的 1 329 520 项测量值。在所有六个年龄性别组中，总体和主要城市的平均 BMIz 均呈小幅显着下降趋势。在高 BMIz 患病率的一些亚组中观察到类似的模式。这些下降趋势似乎部分是由移民解释的。相反，在偏远地区，BMIz 的趋势在所有年龄-性别组和整个社会经济阶层中都在持续增加，尽管并非所有组都具有统计学意义。在整个研究期间，BMIz 根据社会经济地位的不平等持续存在，

解释

这项研究表明，在州一级，2003 年至 2017 年期间，维多利亚州 1、2 和 3·5 岁儿童的平均 BMIz 和高 BMIz 患病率下降。我们发现大都市-地区差异是早期不平等的主要来源儿童 BMIz 趋势，以及地区层面的社会经济地位。这些发现强调了以下风险：对儿童 BMIz 总体趋势的分析可能会根据偏远、社会经济地位和种族等因素掩盖重要的不平等。未来的研究需要使用大量人口样本监测数据，以充分检查人口亚组之间流行率和趋势的差异。

资金

没有任何。