OBJECTIVE: To establish a normal range of values for thyroid volume among adult Filipinos and to correlate thyroid dimensions with age, sex, weight, height, and urinary iodine.
METHODS: This is a cross-sectional study conducted at the University of the Philippines-Philippine General Hospital. Out of 212 health personnel screened, 169 were included based on the following exclusion criteria: goiter stage Ib to III as defined by WHO, hyperthyroid or hypothyroid, hospitalization within the past month, chronic renal disease, chronic alcohol intake, more than 4 pack years of smoking, and abnormal laboratory profile. Laboratory parameters included FT3, FT4, TSH, creatinine, anti-thyroglobulin, anti-thyroid peroxidase, 24-hr urinary iodine , and thyroid ultrasonography. There were 55 males and 114 females with a mean age of 38.98 +/- 11.21 years old, mean weight of 59.84 +/- 11.91 kg.
RESULTS: The size of the right lobe ranged from 3.58-5.09 x 1.15-1.89 x 1.01-1.90 cm (LxWxD) while the left lobe ranged from 3.62-5.01 x 1.15-1.93 x 1.03-1.84, comparable with established values in literature. Using Hotelling's T-squared, male sex was associated with a larger thyroid dimension, (p-value <0.01) There was no statistically significant relationship between thyroid dimension and urinary iodide level. (Pillai's Trace p=0.88, Wilk's Lambda p=0.88, Hotteling's Trace p=0.88, Roy's Largest Root p=0.57). In general, thyroid dimensions were significantly correlated with the demographic variables using canonical correlation (0.5431, p=0.0232).
CONCLUSIONS: The normative thyroid dimensions established among Filipino adults were comparable with the accepted reference values. Thyroid dimensions were significantly correlated with weight, height, and sex but not with urinary iodide levels.