Guatemalan Maya of the same age, largely due to better nutrition and health care. Bogin also noted that American Maya children had relatively longer legs, averaging longer than the Guatemalan Maya (a significantly lower sitting height ratio). The Nilotic peoples of Sudan such as the Shilluk and Dinka have been described as some of the tallest in the world. Dinka Ruweng males investigated by Roberts in 1953–54 were on average tall, and Shilluk males averaged . The Nilotic people are characterized as having long legs, narrow bodies and short trunks, an adaptation to hot weather. However, male Dinka and Shilluk refugees measured in 1995 in Southwestern Ethiopia were on average only and tall, respectively. As the study points out, Nilotic people "may attain greater height if privileged with favourable environmental conditions during early childhood and adolescence, allowing full expression of the genetic material." Before fleeing, these refugees were subject to privation as a consequence of the succession of civil wars in their country from 1955 to the present. The tallest living married couple are ex-basketball players Yao Ming and Ye Li (both of China) who measure and respectively, giving a combined height of . They married in Shanghai, China, on 6 August 2007. In Tibet, the Khampas are known for their great height. Khampa males are on average . Role of an individual's height Height and health Studies show that there is a correlation between small stature and a longer life expectancy. Individuals of small stature are also more likely to have lower blood pressure and are less likely to acquire cancer. The University of Hawaii has found that the “longevity gene” FOXO3 that reduces the effects of aging is more commonly found in individuals of a small body size. Short stature decreases the risk of venous insufficiency. Certain studies have shown that height is a factor in overall health while some suggest tallness is associated with better cardiovascular health and shortness with longevity. Cancer risk has also been found to grow with height. Moreover, scientists have also observed a protective effect of height on risk for Alzheimer's disease, although this fact could be a result of the genetic overlap between height and intracraneal volume and there are also genetic variants influencing height that could affect biological mechanisms involved in Alzheimer's disease etiology, such as Insulin-like growth factor 1 (IGF-1). Nonetheless, modern westernized interpretations of the relationship between height and