Kim and Ruger BMC Public Health 2010, 10:195 http://www.biomedcentral.com/1471-2458/10/195 Table 1: Sociodemographic Indicators Overall and by Income Quintile (1998) (Continued) Education Illiterate Elementary Middle High College & above Marital status Never married Married Single 5.93 21.44 18.55 35.94 18.14 7.70 88.24 4.06 53.80 33.26 20.43 13.99 4.79 42.95 17.52 30.45 14.65 19.47 23.76 22.03 14.46 17.57 20.27 18.52 11.27 15.26 20.88 22.54 22.56 15.84 20.74 11.93 10.42 14.95 17.37 19.42 32.87 11.28 20.86 17.70 Page 5 of 19 9.86 17.06 17.55 22.03 25.32 12.36 20.61 21.40 Calculations subject to rounding errors highest percentage of people with elementary education (33.3%, 37.6%) and those illiterate (53.8%, 55.4%) were in the lowest income class. 88.2% of the 1998 sample and 82.3% in 2005 was married. 43.0% of never-married respondents were in the lowest income class in 1998 compared to 23.4% in 2005. In terms of occupation, 21.3% were housewives, 18.0% service and sales workers and 15.1% were skilled agricultural, forestry and fishery work- ers in 1998. However, the percentage of those in agricul- ture, forestry and fishery decreased significantly to 5.4% in 2005. Individuals in the lowest income class include the unemployed (47.5% in 1998 and 50.4% in 2005), skilled agriculture, forestry, and fishery workers (35.3% in 1998 and 37.4% in 2005), and manual laborers (27.9% in 1998 and 29.2% in 2005), whereas individuals in the high- est income class included legislators, senior officials and managers (39.3% in 1998 and 63.7% in 2005), and profes- sionals (32.9% in 1998 and 57.9% in 2005). Behavioral Risk Factors by Socioeconomic Position Educational Disparities Table 3 and 4 present age-adjusted education disparities in behavioral risk factors by gender. In terms of obesity, women in the elementary group had the highest rates of obesity (41.5%), while women in the college and above group had the lowest obesity rate (16.5%) in 1998. In 2005, more educated women had the highest rates of obe- sity (49.5% in high and 54.2% in college and above) com- pared to illiterate (29.4%) who had the lowest obesity rate. In 1998, the obesity rate for males was highest among the college and above education class (32.9%) and lowest among illiterate respondents (16.0%). In 2005, obesity rates in males were lowest in illiterate (19.7%) and increased to 41.4% in college and above. For exercise, male respondents in the highest education classes (27.0% college and above and 21.1% in high) reported exercising on a regular basis in 1998. However, 91.8% of males and 94.7% of females in the lowest educa- tion class (illiterate) reported no exercise in 1998. Exer- cise rates increased in 2005, with 49.4% of all males and 43.6% of all females exercising regularly, especially among illiterate (38.3%) and elementary (34.5%) men and all edu- cational levels of women (29.4% illiterate; 54.2% college and above). From 1998 to 2005, males became more likely to be obese (28.9% compared to 37.1%), yet also more likely to exercise on a regular basis (22.0% compared to 49.4%). For smoking, for females, the proportion of people who never smoked was higher in the high and college and above education classes (94.4% and 94.1% in 1998, 91.2% and 94.3% in 2005), but was only slightly lower in the illit- erate class (89.6% in 1998 and 91.6% in 2005). Further- more, females in higher education classes (high and college and above) tended to have lower rates of current smoking (3.4% and 2.7%) in 1998; however, the rates increased to 5.7% and decreased to 2.6%, respectively in