The well established factors used are seasonal variation, diurnal variation, solar activity and magnetic activity.
Several clinical variables, such as tumor stage and age, are well established factors associated with long-term survival after surgical resection of lung cancer.
Food intake and its rich composition are well established factors associated with obesity in Saudis [ 7].
Another limitation was that the well established factors such as grade and ER status were not independently associated with cancer specific survival in all patients and in those with node-negative or triple-negative disease.
Although there were more current smokers in both Beijing urban and rural cohorts compared with Hong Kong, smoking was not an independent risk factor even though it is a well established risk factor for many chronic diseases, probably because multi-morbidity had been included as a model, and the survivor effect may be present.
134 More importantly smoking is a strong, independent risk factor for stroke, 135 which is a well established risk factor for dementia.
The presence of family history is a well established risk factor with 25-35% of CRCs attributable to inherited and/or familial factors.
Hypertension is a leading risk factor for mortality in both developing and developed countries (1) and a well established risk factor for cardiovascular disease (CVD) in patients with diabetes (2).
Dyslipidemia, a well established risk factor for ischemic heart disease, has not yet been convincingly demonstrated as a factor associated with VaD or AD.
While alcohol is a well established risk factor for HCC, there is evidence that cigarette smoking is also a risk factor (Mukaiya et al, 1998; Mizoue et al, 2000; Chen et al, 2003), though some studies reported no or an insignificant association (La Vecchia et al, 1988; Evans et al, 2002).
