Results indicate that PTH is positively correlated with BMI (p<0.01, r=0.268). The frequency of high levels of hyperparathyroidism was observed more in obese (9.1%) and severely obese (26.1%) subjects compared to normal (2.5%) and overweight (6.1%) subjects (p=0.001). No association was found between BMI and calcium and phosphate. Z-score based on BMI: normal, -1.0 to +1.0 (15th percentile to 85th percentile); overweight, more than 1.0 (85th percentile); obese, more than 2 (97th percentile); and severely obese, more than 3 (99th percentile). This evidence concerns the gene PTH and hyperparathyroidism.