Table 1.

Distribution of sociodemographics and modifiable risk factors according to lifetime chronic back pain^*

Characteristics	Lifetime Chronic Back Pain
	No (n=5163)	Yes (n=1990)	p value*
Sociodemographics
Age (mean)	61.7	61.0	<0.001
Race (%)
White	93.1%	92.6%	0.50
Non-white	6.9%	7.4%
Educational attainment
Did not graduate high school	4.5%	8.9%	<0.001
High school graduate	24.5%	25.7%
Some college/vocational schoola	44.2%	45.0%
Completed college or further studyb	26.7%	20.4%
Income (annual family income)
$50,000 or more	55.7%	43.7%	<0.001
VA health care user ever	23.5%	35.2%	<0.001
Ever applied for VA disability compensation, for any health condition	19.8%	36.8%	<0.001
Modifiable Lifestyle-Related and Psychological Risk Factors
Body Mass Index
Normal	22.1%	20.3%	<0.001
Overweight	46.7%	44.5%
Obesity I	22.4%	23.1%
Obesity II/III	8.8%	12.2%
Smoking
Never smoked	35.4%	28.0%
Former smoker	44.7%	45.3%	<0.001
Current smoker	20.0%	26.8%
Alcohol (typical # of drinks per day)
Never or no current alcohol	36.2%	43.6%	<0.001
<2 drinks in typical day	43.3%	36.4%
3 or more drinks	20.5%	19.9%
Physical activity [PA] (by moderate-intensity equivalent min/wk)
Inactive (<150 min/wk)	32.1%	39.9%	<0.001
Low PA (150–299 min/wk)	14.8%	12.6%
Moderate PA (300–899 min/wk)	23.2%	20.4%
High PA >900 min/wk)	29.9%	27.1%
Sleep
<6 hours/night	25.0%	40.7%	<0.001
6 to <7 hours/night	25.7%	22.5%
7 to <9 hours/night [ref]	45.8%	32.9%
9+ hours/night	3.5%	3.8%
Depression
No depression (PHQ<5.0)	77.6%	49.0%
Mild Depression (PHQ ≥5.0 and <10.0)	13.1%	23.5%	<0.001
Moderate/Severe Depression (PHQ≥10.0)	9.3%	27.5%
PTSD
No PTSD (PCL<30)	80.1%	53.6%	<0.001
Low PTSD symptoms (PCL ≥30 and <50)	14.3%	26.3%
Severe PTSD symptoms(PCL ≥50)	5.7%	20.1%

VA= Veterans Affairs, min=minutes, wk=week

^*p-values adjusted to account for clustering by twinship

^aIncluding some college without completion, or having completed vocational school, technical school, or a 2-year college degree

^battended and/or completed graduate school\