Table 1.

Smoking Status and other Characteristics of 20,863 Nurses Who Underwent Upper Gastrointestinal Endoscopy.

Characteristic	Smoking Status
	Never	Former	Current
Participants, n	9,214	9,620	2,029
Age	64 (8)	64 (8)	61 (8)
Body mass index*	23 (6)	23 (6)	22 (6)
Regular vigorous exercise, %†	37	39	29
Calories consumed/d	1757 (526)	1728 (516)	1727 (515)
Alcohol use, g/d	3 (7)	6 (9)	7 (12)
Postmenopausal, %‡	94	95	92
Never used hormones,%	26	25	32
Past use of hormones,%	27	29	28
Current use of hormones,%	47	46	40
Heartburn/acid-reflux symptoms, %∥	54	57	49
Regular use of acid-suppression medication, %§	15	16	13

Values were calculated from the most recent questionnaire before index endoscopy except heartburn/acid-reflux symptoms (asked only in 2002) and body mass index which represents a cumulative average between 1976 and the most recent questionnaire before endoscopy. Continuous variables are given as means (SD).

^*Body mass index = weight in kilograms divided by the square of the height in meters.

^†Regular vigorous exercise was defined as vigorous physical activity (enough to work up a sweat) for 1 or more days per week or for 10.6 or more metabolic equivalents per week.

^‡Hormones are defined as postmenopausal estrogen or estrogen and progesterone preparations. Percentage of never, past, and current use was calculated among postmenopausal women only.

^∥Heartburn/acid-reflux symptoms experienced regularly, 1 or more times a week

^§Acid-suppression medications included histamine type-2 receptor antagonists or proton-pump inhibitors used regularly.