Elevated serum immunoglobulin G4 (IgG4) concentrations are one of the characteristic findings in IgG4-related disease (IgG4-RD). This study investigated the frequency of elevated serum IgG4 levels and associated factors in a general Japanese population. Serum IgG4 concentrations were measured in 1,201 residents of Ishikawa prefecture who underwent general medical examinations. Factors associated with elevated serum IgG4 concentrations were assessed by logistic regression analysis. Participants with elevated serum IgG4 were subjected to secondary examinations. The mean serum IgG4 concentration was 44 mg/dL, with 42 (3.5%) participants having elevated serum IgG4 levels. Age- and sex-adjusted logistic regression analyses showed that male sex, older age, and lower intake of lipids and polyunsaturated fatty acids and higher intake of carbohydrates in daily diet were associated with elevated serum IgG4 concentration. Subgroup analyses in men showed that older age, lower estimated glomerular filtration rates based on serum cystatin C (eGFR-cysC) levels, and higher hemoglobin A1c (HbA1c) levels were associated with elevated serum IgG4 concentration. Analyses in women showed that lower intake of lipids and fatty acids and higher intake of carbohydrates were significantly associated with elevated serum IgG4 concentration. One of the 15 participants who underwent secondary examinations was diagnosed with possible IgG4-related retroperitoneal fibrosis. Elevated serum IgG4 levels in a Japanese general population were significantly associated with older age, male gender, and dietary intake of nutrients, with some of these factors identical to the epidemiological features of IgG4-RD.

中文翻译：

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日本普通人群血清免疫球蛋白 G4 (IgG4) 水平升高的相关因素


血清免疫球蛋白 G4 (IgG4) 浓度升高是 IgG4 相关疾病 (IgG4-RD) 的特征性表现之一。本研究调查了一般日本人群中血清 IgG4 水平升高的频率以及相关因素。对石川县 1,201 名接受一般体检的居民进行了血清 IgG4 浓度测量。通过逻辑回归分析评估与血清 IgG4 浓度升高相关的因素。血清 IgG4 升高的参与者接受了二次检查。平均血清 IgG4 浓度为 44 mg/dL，其中 42 名 (3.5%) 参与者血清 IgG4 水平升高。年龄和性别调整后的逻辑回归分析显示，男性、年龄较大、日常饮食中脂质和多不饱和脂肪酸摄入量较低以及碳水化合物摄入量较高与血清 IgG4 浓度升高相关。男性亚组分析显示，年龄较大、基于血清胱抑素 C (eGFR-cysC) 水平的估计肾小球滤过率较低以及糖化血红蛋白 (HbA1c) 水平较高与血清 IgG4 浓度升高相关。对女性的分析表明，较低的脂质和脂肪酸摄入量以及较高的碳水化合物摄入量与血清 IgG4 浓度升高显着相关。接受二次检查的 15 名参与者中，有一名被诊断出可能患有 IgG4 相关的腹膜后纤维化。日本普通人群中血清 IgG4 水平升高与年龄较大、男性和膳食营养素摄入量显着相关，其中一些因素与 IgG4-RD 的流行病学特征相同。