Table 1.

Characteristics of Women Enrolled in the Lung Cancer Susceptibility Study, Boston, Massachusetts, 1992–2004

	Cases (n = 1,004)			Controls (n = 848)			P Valuea
	No.	%	Median (SD)	No.	%	Median (SD)
Age, years			66.2 (10.8)			58.4 (11.4)	<0.001
Caucasian race	973	97		824	97		0.75
Education
Less than high school	130	15		73	9		<0.001
High school	348	40		278	33		0.003
Some college or college degree	385	45		485	58		<0.001
Missing data	141			12
Smoking status
Never smoker	102	10		332	39		<0.001
Current smoker	430	43		188	22		<0.001
Former smoker	472	47		328	39		<0.001
Pack-years of smoking
Former smoker			41.7 (30.5)			16.6 (20.7)	<0.001
Current smoker			48.4 (32.5)			31.9 (25.3)	<0.001
Histologic type
Adenocarcinoma	455	45
Squamous-cell carcinoma	150	15
Bronchoalveolar carcinoma	121	12
Other	278	28
Nulliparity	149	15		117	14		0.52

Abbreviation: SD, standard deviation.

^aP value from a χ² test for categorical variables and a t test for continuous variables. All P values are 2-sided.