Nicholas Kristof: We humans make a lonely crowd, and it’s killing us

London — We humans make a lonely crowd, and it’s killing us.Social isolation is more lethal than smoking 15 cigarettes a day, or than obesity, according to research published by Julianne Holt-Lunstad of Brigham Young University. Since obesity is associated in the United States with 300,000 to 600,000 deaths a year, the implication is that loneliness is a huge, if silent, killer.Loneliness increases inflammation, heart disease, dementia and death rates, researchers say — but it