In a prospective study with 2,871 elderly people, those in the high leptin group had lesser likelihood of developing cognitive decline over 4 years than those in the lower group (OR = 0.66; 95% CI 0.48–0.91, after adjustment for age, race, gender, education, baseline cognitive score, hypertension, prior MI, diabetes, number of days spent in the hospital in the prior 5 years, BMI and total percentage of body fat) (37). Here, LEP is linked to diabetes mellitus.