How strong is the evidence for Healthy Aging Lifestyle?

A widely cited BMJ cohort study following US health professionals over decades found that people who maintained five low-risk lifestyle factors (never smoking, healthy weight, regular physical activity, moderate alcohol intake, and a quality diet) lived on average many years longer free of cancer, cardiovascular disease and type 2 diabetes than those who maintained none. That evidence is currently rated strong (90/100), built on 7 published studies, including 2 meta-analyses -- enough for real confidence in the effect.