This study evaluates whether achieving 25-hydroxyvitamin D (25[OH] Vit D) levels (>40 ng/mL) among myocardial infarction patients will result in a reduction of cardiovascular-related adverse events. Half of the patients will be randomized to receive standard of care and half will receive clinical management of 25[OH] Vit D levels.

Low 25[OH] Vit D levels have become a public epidemic with increasing recognition of its widespread insufficiency both in the United States and worldwide. Epidemiologic studies have associated low 25[OH] Vit D levels with coronary risk factors and adverse cardiovascular outcomes. However, randomized trials are needed to establish the relevance of 25[OH] Vit D status to cardiovascular health. While a few randomized trials have evaluated vitamin D supplementation, none have "treated to target" (i.e., individual dosing so that adequate 25[OH] Vit D levels are obtained), but have rather given "blanket" doses regardless of 25[OH] Vit D level.

Inclusion Criteria:

1. Patients, both male and female, >18 years old
2. Undergone angiography for a MI (troponin positive [>0.04 ng/mL] and ACS diagnosis) within the past month
3. Receive follow-up care at an Intermountain Healthcare facility
4. Not taking or taking <1000 IU of vitamin D daily within the last 3 months
5. Willing to provide informed consent and participate in follow-up visits

Exclusion Criteria:

1. Hypersensitivity to vitamin D products
2. History of previous vitamin D supplementation of >1000 IU daily within the past 3 months (i.e., >40% of the days during the past 3 months).
3. Systemic disease (including terminal cancer, cirrhosis, end stage COPD, etc) with a reduced (<12 months) life expectancy
4. Hypercalcemia (calcium levels >10.6 mg/dL)
5. Subject participation in previous investigational interventional studies within 30 days of the current study.
6. History of psychiatric illness/condition that would interfere with their ability to understand or complete the requirements of the study, a condition that in the opinion of the investigator or their designee places the subject at an unacceptable risk as a participant.
7. Pregnant and/or lactating women and women of child bearing potential who are not using acceptable means of contraception as determined by the clinical investigators.