Table 1.

Characteristics of the myotonic dystrophy type I (DM1)‐affected patients and their matched DM1‐free controls.

Characteristics	DM1 (n = 927)	DM1‐free (n = 13,085)
Age at DM1 diagnosis, <i>n</i> (%)
Congenital/childhood (0–10 years)	132 (14%)	–
Classic (11–40 years)	500 (54%)	–
Late‐onset (>40 years)	295 (32%)	–
Mean age at diagnosis, mean (SD)	31.2 (17.8)	–
Gender, n (%)
Male	455 (49%)	6,474 (49%)
Female	472 (51%)	6,611 (51%)
Benign tumor
All sites combined, n (%)	132 (14%)	800 (6%)
Age at first tumor, mean (SD)	43.8 (14.6)	42.0 (15.0)
Tumor status
None	762 (82%)	11,660 (89%)
Benign only	124 (13%)	717 (5%)
Malignant only	33 (4%)	625 (5%)
Benign and malignant	8 (1%)	83 (1%)
Follow‐up time
Median (range)	5.6 (0‐28.2)	3.7 (0‐28.2)
Total, Person‐years	7,100.7	73,076.5