A vicious cycle of frailty and acute lower respiratory infection among community-dwelling adults (≥ 60 years): Findings from a multi-site INSPIRE cohort study, India - Siddhartha Saha; Ritvik Amarchand; Rakesh Kumar; Aslesh O. Prabhakaran; Prabu Rajkumar; Sumit Dutt Bhardwaj; Suman Kanungo; Radhika Gharpure; Kathryn E. Lafond; Eduardo Azziz-Baumgartner; Anand Krishnan (PLOS Global Public Health)