Heber J. Grant was the seventh prophet of The Church of Jesus Christ of Latter-day Saints. He was prophet through some of the hardest times the world has ever seen including World War II, and the Great Depression. It is not surprising that during the this challenging time in the world, this was when the Temple Questions were changed to ask, if each person, is living the World of Wisdom.
President Heber J. Grant had a close childhood friend who went on a mission after getting 'a bit' involved in drinking. This friend came home from his mission, and went out again.
President Grant stood at graveside of this dear childhood friend, when he died of Cirrhosis of the liver, and he was in his early thirties.
While standing at the graveside of his childhood friend, President Grant looked up and said "I swear before the Living God I will be an enemy of alcohol for the rest of my life."
President Grand stayed true to his word, working to help people understand the detriment of drugs and alcohol by changing the policy of the Church to include the obedience to the Word of Wisdom in the temple recommend interview.
In 1921, only three years after Heber J. Grant became Prophet of The Church of Jesus Christ of Latter-day Saints, the Word of Wisdom question was added to the temple recommend interview. The Word of Wisdom was given to the Joseph Smith in 1833, almost a hundred years before it was added to the temple recommend questions.
References:
"Presidents of the Church" by Truman G. Madsen chapter 7