Some of the variation in weight that is not. accounted for in Tables 1 or 2 is due to the variation. in the wood density of the different species. AdjustÂ­. ment factors have been developed to account for the. variation by species. The adjustment factors were. each species by the average density of all of the trees.
For example, regular smoking increases the risk of developing lung cancer; therefore smoking is a risk factor for lung cancer. The risk factors for mouth cancer include: 1  Smoking - studies indicate that a 40-per-day smoker has a risk five times great than a lifetime non-smoker of developing oral cancer.  Chewing tobacco.
Several types of malignant cancers occur in the mouth and throat. 1  Squamous cell carcinoma is by far the most common type, accounting for more than 90% of all cancers. These cancers start in the squamous cells, which form the surface of much of the lining of the mouth and pharynx.