North Carolinians have grown considerably more obese (body mass index ???30 [calculated as weight in kilograms divided by height in meters squared]) over the period we examined (13.4% in 1992 to 26.6% in 2006).47 Whether obesity is a risk factor for LBP, however, is still unclear.48- 50 Changes in psychosocial and physical work demands, risk factors for LBP,51 may have also contributed to the incr