Background

Recent studies suggest that greater exposure to natural vegetation, or “green space” is associated with lower diabetes risk, possibly through increasing physical activity. However, there is limited research on green space and insulin resistance in youth. We hypothesized greater green space at early-life sensitive time periods would be associated with lower insulin resistance in youth.

Methods

We used data from Project Viva (N = 460), a pre-birth cohort study that recruited pregnant women in eastern Massachusetts, 1999–2002, and followed offspring into adolescence. We defined residential green space exposure at infancy (median age − 1.1 years), early childhood (3.2 years), mid-childhood (7.7 years), and early adolescence (12.8 years), using 30 m resolution Landsat satellite imagery to estimate the Normalized Difference Vegetation Index [NDVI]. Our main outcome was early adolescence estimated insulin resistance (HOMA-IR). We used multiple imputation to account for missing data and multiple linear regression models adjusted for age, sex, race/ethnicity, parental education, household income, and neighborhood median household income.

Results

The highest green space tertile had the highest percentage of white participants (85%), college-educated mothers (87%) and fathers (85%), and households with income higher than US$70,000 (86%). Unadjusted models showed that participants living in the highest green space tertile at infancy had a 0.15 unit lower HOMA-IR (95% CI: −0.23, −0.06) in early adolescence, than those living in the lowest tertile. However, in adjusted models, we did not observe evidence of associations between green space from infancy to early adolescence and HOMA-IR in early adolescence, although some point estimates were in the hypothesized direction. For example, participants in the highest green space tertile in infancy had 0.03 units lower HOMA-IR (95%CI: −0.14, 0.08) than those living in the lowest tertile.

Conclusions

Exposure to green space at early life sensitive time periods was not associated with HOMA-IR in youth. Early-life longitudinal studies across diverse populations are needed to confirm or refute our results.

中文翻译：

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早期生活暴露于绿色空间和胰岛素抵抗：从婴儿期到青春期早期的评估。

背景

最近的研究表明，更多地接触自然植被或“绿色空间”与降低糖尿病风险有关，这可能是通过增加体育锻炼来实现的。然而，关于青年绿地和胰岛素抵抗的研究有限。我们假设在生命早期敏感时期更大的绿地与青年较低的胰岛素抵抗有关。

方法

我们使用来自 Project Viva (N = 460) 的数据，这是一项出生前队列研究，于 1999-2002 年在马萨诸塞州东部招募孕妇，并跟踪后代进入青春期。我们定义了婴儿期（中位年龄 - 1.1 岁）、儿童早期（3.2 岁）、儿童中期（7.7 岁）和青春期早期（12.8 岁）的住宅绿地暴露，使用 30 m 分辨率的 Landsat 卫星图像来估计标准化差异植被指数 [NDVI]。我们的主要结果是青春期早期估计的胰岛素抵抗（HOMA-IR）。我们使用多重插补来解释缺失的数据，并使用多重线性回归模型根据年龄、性别、种族/民族、父母教育、家庭收入和邻里家庭收入中位数进行调整。

结果

在绿地面积最高的三分位数中，白人参与者 (85%)、受过大学教育的母亲 (87%) 和父亲 (85%) 以及收入高于 70,000 美元的家庭 (86%) 的比例最高。未经调整的模型显示，与生活在最低三分位数的参与者相比，生活在婴儿期最高绿色空间三分位数的参与者在青春期早期的 HOMA-IR（95% CI：-0.23，-0.06）低 0.15 个单位。然而，在调整后的模型中，我们没有观察到从婴儿期到青春期早期的绿色空间与青春期早期的 HOMA-IR 之间关联的证据，尽管一些点估计是在假设的方向上。例如，处于婴儿期最高绿色空间三分位数的参与者的 HOMA-IR (95%CI: -0.14, 0.08) 比生活在最低三分位数的参与者低 0.03 个单位。

结论

在生命早期敏感时期暴露于绿色空间与青年时期的 HOMA-IR 无关。需要对不同人群进行早期纵向研究来证实或反驳我们的结果。