Table 1.

Summary measures and frequency distributions of age, BMI, smoking, and 12MR score.

Characteristic	Mean (SD)	Median	Minimum	Maximum	N (% of subjects)
Age	19.52 (0.81)	19.43	17.48	24.79
BMI (continuous)	22.47 (3.27)	21.91	15.35	34.88
BMI (categorical)
Underweight			15.35	18.50	130 (8.0)
Normal weight			18.51	24.96	1,191 (73.1)
Overweight/obese			25.00	34.88	308 (18.9)
Smoking
No smoking					689 (42.3)
Occasional smoking					395 (24.3)
Regular smoking					545 (33.5)
12MR score (continuous)	2,533.1 (336.4)	2,550.0	1,200	3,740
12MR score (categorical)
Low (first quantile)			1,200	2,260	325 (20.0)
Intermediate (quantiles 2 and 3)			2,265	2,620	653 (40.1)
High (quantiles 4 and 5)			2,625	3,740	651 (40.0)

12MR, Cooper’s 12-minute run test; BMI, body mass index; N, number of subjects.