Background

Epidemiologic studies on the association between metals and body mass index (BMI) have been cross-sectional and have demonstrated inconsistent associations. Our study prospectively examined whether metals measured at baseline were associated with later BMI. We considered metals individually and as joint exposure to pre-defined metal groupings.

Methods

We measured concentrations of 16 metals in toenails collected at baseline (2003–2009) in a subset of 1221 women from the Sister Study. We calculated BMI from height and weight reported on a follow-up questionnaire an average of 5.2 years (range = 3.5–8.3) after baseline. Multivariable linear regression was used to estimate β coefficients and 95% confidence intervals (CIs) for associations between BMI and individual metals (with estimates given per interquartile range (IQR) increase or in quartiles). Quantile g-computation was used to examine joint associations between groups of metals and BMI. Groups considered were (1) all metals combined, and metals classified as (2) non-essential or (3) essential.

Results

In individual metal models we found that, with the exception of cobalt, no single metal was strongly related to BMI. In our mixture analyses, a quartile increase in all non-essential metals was associated with higher BMI (β = 0.32; 95%CI: 0.00, 0.63 kg/m²), whereas essential metals were suggestively associated with lower BMI (β = −0.25; 95%CI: 0.58, 0.07 kg/m²).

Conclusions

In this population of women who were, on average, overweight, essential metals were jointly associated with slightly healthier, lower BMI whereas non-essential metals were jointly associated with slightly higher, unhealthier BMI, after controlling for other health indicators and predictors of metals exposures.

中文翻译：

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在美国女性的前瞻性研究中，金属和微量元素与体重指数的关系。

背景

关于金属和体重指数（BMI）之间关联的流行病学研究已经横断面，并且证明了不一致的关联。我们的研究前瞻性地检查了基线测量的金属是否与以后的BMI相关。我们将金属单独考虑为共同接触预定义金属组的元素。

方法

我们测量了Sister研究中1221名女性的基线时（2003-2009年）在脚趾甲中收集的16种金属的浓度。我们根据基线后平均5.2年（范围= 3.5–8.3）的随访问卷中报告的身高和体重计算出BMI。多变量线性回归用于估计BMI与单个金属之间的关联的β系数和95％置信区间（CIs）（估计值根据四分位数间距（IQR）的增加或四分位数给出）。分位数g计算用于检查金属与BMI之间的联合关联。所考虑的组是（1）所有金属的总和，以及分类为（2）非必需或（3）必需的金属。

结果

在单个金属模型中，我们发现，除钴外，没有任何一种金属与BMI密切相关。在我们的混合分析中，所有非必需金属的四分位数增加与较高的BMI有关（β  = 0.32; 95％CI：0.00，0.63 kg / m ²），而必需金属与较低的BMI有关（β  = − 0.25； 95％CI：0.58，0.07kg / m ²）。

结论

在控制了其他健康指标和金属暴露预测指标之后，在平均超重，必需金属与体重指数稍健康，较低的女性人群中，而非必需金属与体重指数较高，较不健康的女性共同较高。 。