Instead, they publish both negative and positive results related to things they were interested in from the start. They find how things are.
The Finnish Vitamin D Trial (FIND) is very large randomized, double-blind, placebo-controlled, 5-year supplementation study of the benefits and risks of vitamin D in the primary prevention of cardiovascular (CVD) and cancer among 18000 men 60 years or older and women 65 years or older. https://classic.clinicaltrials.gov/ct2/show/NCT01463813