Aging is also a very serious social problem globally. It has been reported that the number of people aged sixty years and above is estimated to increase by more than triple, especially in developed countries, where elderly people are expected to account for at least one-third of the total population within the next fifty years [8]. As shown in many studies, aging leads to a series of problems, with the most concern being the escalating medical expenditures and higher morbidity and mortality [9,10]. It is noted that those problems tend to be worse in rural areas than that in urban areas due to unbalanced economic development and an unequal distribution of health care resources