Yost et al. BMC Public Health 2010, 10:465 http://www.biomedcentral.com/1471-2458/10/465 Table 3 Descriptive Statistics for Body Mass Index (BMI) Percentile, Weight Perception, Trying to Lose Weight, and Exercise as a Weight-Loss Method (N = 2216) Variables (n) BMI Percentile (2163) Mean (Standard Deviation) Median Not overweight or obese Overweight Obese Weight Perception (2215) Not overweight Slightly overweight Very overweight Trying to Lose Weight at Wave II (2215) Not trying to lose weight Trying to lose weight Exercise as a Weight-Loss Method if Trying to Lose Weight (1040) No Yes n % 22.90 (5.18) 21.63 1571 72.63 336 15.53 256 11.84 1351 60.99 757 34.18 107 4.83 1,175 53.05 1,040 46.95 244 23.46 796 76.54 Pacific Islander female adolescents were the least likely to be overweight compared to female adolescents in all other racial categories (p < 0.01). Weight Perception In the study’s sample, most female adolescents perceived themselves as not overweight (60.99%) (see Table 3). American Indian/Native American female adolescents and female adolescents in the “Other” race category were most likely to perceive themselves as overweight. Chi-square statistics demonstrated that American Indian/Native American and “Other” female adolescents were significantly more likely than Black/African Ameri- can female adolescents to perceive themselves as overweight (p < 0.05). Subjects in the “Other” race category were also significantly more likely than their White counterparts to perceive themselves as over- weight (p < 0.05). Accuracy of Weight Perception In addition to descriptive statistics, chi square statistics demonstrated a significant difference in the accuracy of female adolescents’ weight perception, based on their actual BMI weight classification. Of the female adoles- cents who were overweight or obese, 79.06% accurately perceived themselves as either slightly or very over- weight (p < 0.05). In addition, almost 20% of the over- weight or obese female adolescents inaccurately underestimated their weight as not overweight (see Table 4). Significant racial differences also existed in the sub- jects’ accuracy of weight perception. Overweight or obese Black/African American female adolescents were Page 6 of 11 more likely to underestimate their weight than were White (p < 0.01), Asian (p < 0.01), or Other (p < 0.05) female adolescents. In addition, overweight or obese American Indian/Native American female adolescents were significantly more likely than their Asian counter- parts to underestimate their weight (p < 0.05). Trying to Lose Weight Approximately half of the female adolescents in the sample were currently trying to lose weight, while the other half indicated they were not currently trying to lose weight (see Table 3). Across all models used in the study, age was significantly associated with trying to lose weight: With each increasing year in age, subjects were more likely to be trying to lose weight (OR = 1.07-1.18, p < 0.05) (see Table 5). In the third model (demographic variables, plus variables indicating weight perception accuracy), race was significantly associated with trying to lose weight: Black/African American subjects were 0.6 times less likely to be trying to lose weight than their White counterparts. A significant positive associa- tion with also emerged between BMI and weight per- ception. Overweight and obese subjects were two to four times more likely to be trying to lose weight than subjects who were not overweight or obese. Also, sub- jects who perceived themselves as slightly or very over- weight were 13 to 25 times more likely to be trying to lose weight than subjects who did not perceive them- selves as slightly or very overweight (see Table 5). Wald statistics indicated that, compared to the over- weight subjects, the obese subjects were significantly more likely to be trying to lose weight (F = 6.72, p < 0.0006), with no difference between a weight perception of slightly overweight and very overweight (F = -0.96, p 0.392). In addition, compared to the variable of BMI, the variable of weight perception was significantly asso- ciated with greater odds of trying to lose weight; Wald statistics were significant (p < 0.05) for the difference between these two variables. All weight perception accu- racy variables were also positively associated with trying to lose weight. Overweight or obese subjects who accu- rately perceived their weight as either slightly or very overweight were significantly more likely to be trying to lose weight than overweight or obese subjects who inac- curately underestimated their weight as not overweight (F = 38.94, F = 17.98, respectively p = 0.000). Although subjects who were overweight or obese and perceived themselves as overweight were the most likely to be try- ing to lose weight (OR = 22.62), no significant difference emerged between these subjects and those who were overweight or obese and perceived themselves as slightly overweight (F = 0.72, p = 0.3690). Engaging in Exercise as a Weight-Loss Method Among the subjects who were currently trying to lose weight (46.95%), the majority reported engaging in