Classification tree for detection of single-nucleotide polymorphism (SNP)-by-SNP interactions related to heart disease: Framingham Heart Study

Table 1 Descriptive statistics of selected traits by generation: range, percentage distribution or mean, and standard deviation at baseline

Trait^a	Generation 1 (n= 356)			Generation 2 (n= 2556)			Generation comparison	Overall (n= 2912)
	Range	Mean	SD	Range	Mean/%	SD		Range	Mean/%	SD
Age	29-54	34.87	3.79	5-59	33.72	9.26	t = 2.31^b	5-59	33.86	8.78
Body Mass Index	16.7-36.0	23.81	3.27	13.5-51.1	24.94	4.10	t = -4.95^c	13.5-51.1	24.80	4.03
SBP	90-160	123.01	13.45	78-200	119.13	14.24	t = 4.86^c	78-200	119.60	14.20
DBP	50-105	77.85	9.35	48-120	77.16	9.97	t = 1.23	48-120	77.25	9.90
Cholesterol	129-339	191.91	37.28	101-388	190.13	36.23	t = 0.68	101-388	190.26	36.30
Cigarettes	0-50	7.58	10.71	0-88	7.60	12.09	t = -0.03	0-88	7.60	12.00
Smoke	0-2			0-2			χ² = 25.97^c	0-2
	0	44.09%		0	41.27%			0	41.46%
	1	5.38%		1	20.01%			1	19.01%
	2	50.54%		2	38.72%			2	39.52%
Diabetes	0-1			0-1			χ² = 2.24	0-1
	0	92.13%		0	89.59%			0	89.90%
	1	7.87%		1	10.41%			1	10.10%

^aSBP, systolic blood pressure (mm Hg); DBP, diastolic blood pressure (mm Hg); Cholesterol, fasting × total cholesterol (mg/dl); Cigarettes, number of cigarettes smoked per day; Smoke, smoking status (0, never; 1, former; 2, current); Diabetes, diabetes status (0, No; 1, Yes).
^bp < 0.05
^cp < 0.001

ISSN: 1753-6561