Association of thoracic kyphosis with some anthropometric variables in Iranian population

As yet, there is no general agreement on normal degree of thoracic kyphosis and associated variables on it. Among different important variables which could have an effect on kyphosis, however, age, BMI, sex is considered to be more important. Nevertheless, literature is leaking comprehensive studies in this issue. Therefore, this study is aimed in investigating of the association of some anthropometric factors such as age, BMI and sex on thoracic kyphosis. In this study, 2549 subjects including of 1312 female and 1237 male between the ages of 7 to 100 years were recruited from 5 different geographical parts of Iran. Flexible ruler was used to measure thoracic kyhposis between the T2 to T12 vertebrae. 10 measurers were used to collect the data (5 male and 5 female). The measurers participated in a instructional workshop where they were cheeked on body landmark identifications and kyphosis measurements using flexible ruler. The reliability result for 10 measurers on kyphosis measurements were high (ICC=0/87). Using Pearson Product Moment, there was a significant positive correlation between the age and TK in male and female as a whole (r=.469; p<.001) and in male and female in separate groups (r=.362; p<.001 and r=.555; p<.001) respectively. Using Pearson product moment, it was a significant positive correlation between the BMI and thoracic in subjects as a whole (r=0.277, p>001) and among genders, male and female (r=0.219; p<.001 and r=0.319; p<.001) separately.  However, running the correlation for participant, male and females as hole, on the BMI of 25 onward (n=900) and for the BMI of 30 onward (n=154) the association was not significant (r=0.046; p=0.164 and r=0.083; p=0.307) respectively. Our study revealed that there is an association between TK and age in both genders. Our study indicated that the TK increase by age in both genders however the rate of incensement in adult females is higher than their male counterparts. This is well supported in the literature to be related to the females’ specific characteristics. Our study also revealed that there is an association between BMI with TK. However, as we found no direct report in the association of TK with the above variable in the literature, further studies needs in this issue.