Fig. 2
From: Relationship between caffeine intake and thyroid function: results from NHANES 2007–2012
Association between Serum TSH and Caffeine in the Overall Population. (A): Nonlinear Relationship Evaluation using the RCS Model. (B): Relationship between Serum TSH and Caffeine Intake through Multivariable Linear Regression. Adjustments were made for various factors, including subgroups, race, cancer, comorbidities, urinary iodine, and intake of micronutrients (selenium, vitamin D, calcium, zinc, iron, magnesium) and macronutrients (protein, carbohydrate, and fat). Caffeine, TSH, urinary iodine, and micronutrient intake were log-transformed. A total of 24 subjects were excluded from regression due to missing data in cancer (n = 3) and urinary iodine (n = 21)