Supplementary Material for: Circulating Polyunsaturated Fatty Acids as Biomarkers for Dietary Intake across Subgroups: The CODAM and Hoorn Studies

<b><i>Aims:</i></b> To evaluate whether participant characteristics and way of expressing circulating fatty acids (FA) influence the strengths of associations between self-reported intake and circulating levels of linoleic acid (LA), alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). <b><i>Methods:</i></b> Cross-sectional analyses were performed in pooled data from the CODAM (<i>n</i> = 469) and Hoorn (<i>n</i> = 702) studies. Circulating FA were measured by gas liquid chromatography and expressed as proportions (% of total FA) and concentrations (µg/mL). Dietary intakes were calculated from a validated food frequency questionnaire. Effects of participant characteristics on associations between dietary and circulating FA were calculated using interaction analyses. <b><i>Results:</i></b> Standardized regression coefficients between dietary FA and proportions of circulating FA (% of total FA) were LA β = 0.28, ALA β = 0.13, EPA β = 0.34, and DHA β = 0.45. Body mass index (BMI), waist circumference, and presence of CVD influenced associations for LA; gender influenced LA, EPA, and DHA; alcohol intake influenced LA and DHA; and glucose tolerance status influenced ALA (<i>p</i> values interaction &lt;0.05). Coefficients for circulating FA as concentrations were LA β = 0.19, ALA β = 0.10, EPA β = 0.31, and DHA β = 0.41. <b><i>Conclusions:</i></b> This study suggests that characteristics such as BMI, alcohol intake, and expressing circulating FA as proportions or concentrations, influence associations between dietary and circulating FA.

<b><i>研究目的：</i></b> 本研究旨在探讨受试者特征以及循环脂肪酸（FA）的表达形式，是否会影响自我报告的膳食摄入量与亚油酸（LA）、α-亚麻酸（ALA）、二十碳五烯酸（EPA）及二十二碳六烯酸（DHA）循环水平之间的关联强度。
<b><i>研究方法：</i></b> 本研究对CODAM研究（<i>n</i>=469）与Hoorn研究（<i>n</i>=702）的合并数据进行横断面分析。采用气相色谱法检测循环脂肪酸（FA），并以占总脂肪酸的百分比（% of total FA）及浓度（µg/mL）两种形式进行表达。膳食摄入量通过经过验证的食物频率问卷进行计算。采用交互分析，评估受试者特征对膳食脂肪酸与循环脂肪酸之间关联的影响。
<b><i>研究结果：</i></b> 膳食脂肪酸与循环脂肪酸占比（% of total FA）之间的标准化回归系数分别为：亚油酸（LA）β=0.28、α-亚麻酸（ALA）β=0.13、二十碳五烯酸（EPA）β=0.34、二十二碳六烯酸（DHA）β=0.45。体重指数（BMI）、腰围及心血管疾病（CVD）患病情况会影响亚油酸（LA）的关联强度；性别会影响亚油酸（LA）、二十碳五烯酸（EPA）及二十二碳六烯酸（DHA）的关联强度；酒精摄入量会影响亚油酸（LA）与二十二碳六烯酸（DHA）的关联强度；糖耐量状态会影响α-亚麻酸（ALA）的关联强度（交互检验<i>p</i>值<0.05）。以浓度形式表达的循环脂肪酸的标准化回归系数分别为：亚油酸（LA）β=0.19、α-亚麻酸（ALA）β=0.10、二十碳五烯酸（EPA）β=0.31、二十二碳六烯酸（DHA）β=0.41。
<b><i>研究结论：</i></b> 本研究表明，体重指数（BMI）、酒精摄入量以及循环脂肪酸的表达形式（百分比或浓度），均会对膳食脂肪酸与循环脂肪酸之间的关联产生影响。