Was Alexander the Great Responsible for Creating Shangri-La in the Hunza Valley in Pakistan?

In his book Lost Horizon (1933) James Hilton created the legend of Shangri-La, a peaceful Himalayan valley of long-lived people.  Where the northern border of the Gilgit-Baltistan region of Pakistan meets China, Afghanistan and Tajikistan, lies the hidden Hunza Valley. Scarcely 160 kilometers (100 miles) long and only 1.6 kilometers (one mile) wide, the nestled valley is framed by the Tien-Shan mountain to the north, the Hindu-Kish mountain to the west, the Kara-Korum mountain to the east and the southern Himalayan mountain range. Remote, inaccessible and sheltered, the Hunzakuts have managed to preserve and protect their culture and their secret to longevity from the modern world.  While researching the Himalayan brown bear in 2010, conservationist and adventurer Willem Daffue, found himself in a position where his mountaineering expedition went awry due to the worst floods in Pakistan in centuries. Stranded in the Hunza Valley, he met these remarkable people, whom legends refer to as reaching ages well beyond the centenary mark.