25-Hydroxyvitamin D response to graded vitamin D3 supplementation among obese adults.

CONTEXT: Guidelines have suggested that obese adults need 2 to 3 times more vitamin D than lean adults to treat vitamin D deficiency, but few studies have evaluated the vitamin D dose response in obese subjects. OBJECTIVE: The purpose of this study was to characterize the pharmacokinetics of 25-hydroxyvitamin D [25(OH)D] response to 3 different doses of vitamin D3 (cholecalciferol) in a group of obese subjects and to quantify the 25(OH)D dose-response relationship. DESIGN, SETTING, INTERVENTION, PATIENTS: This was a randomized, single-blind study of 3 doses of oral vitamin D3 (1000, 5000, or 10,000 IU) given daily to 67 obese subjects for 21 weeks during the winter months. MAIN OUTCOME MEASURES: Serum 25(OH)D levels were measured at baseline and after vitamin D replacement, and 25(OH)D pharmacokinetic parameters were determined, fitting the 25(OH)D concentrations to an exponential model. RESULTS: Mean measured increments in 25(OH)D at week 21 were 12.4 ± 9.7 ng/mL in the 1000 IU/d group, 27.8 ± 10.2 ng/mL in the 5000 IU/d group, and 48.1 ± 19.6 ng/mL in the 10,000 IU/d group. Steady-state increments computed from the model were 20.6 ± 17.1, 35.2 ± 14.6, and 51.3 ± 22.0 ng/mL, respectively. There were no hypercalcuria or hypercalcemia events during the study. CONCLUSION: Our data show that in obese people, the 25(OH)D response to vitamin D3 is directly related to dose and body size with ∼2.5 IU/kg required for every unit increment in 25(OH)D (nanograms per milliliter).

Influence of smoking on the location of acute myocardial infarctions.

Objective. To determine whether there is an association between smoking and the location of acute myocardial infarctions. Methods. Using a cohort from our hospital and published cohorts from Ireland, Uruguay, and Israel, we calculated odds of having an inferior wall as opposed to an anterior wall acute myocardial infarction among smokers and nonsmokers. Results. In our cohort, there was a higher proportion of smokers than nonsmokers in patients with inferior acute myocardial infarctions than in patients with anterior infarctions. This difference was also present in each of the other cohorts. Odds ratios for an inferior versus an anterior acute myocardial infarction among smokers ranged from 1.15 to 2.00 (median odds ratio, 1.32). When the cohorts were combined (n = 3, 160), the pooled odds ratio for an inferior as opposed to an anterior acute myocardial infarction among smokers was 1.38 (95% confidence interval, 1.20 to 1.58) (P < .002). Conclusions. Cigarette smoking increases the risk of inferior wall acute myocardial infarction more than the risk of anterior wall infarction. Smoking thus appears to adversely affect the right coronary arterial circulation to a greater extent than the left coronary arterial circulation by a mechanism not yet understood.

Relation of nausea and vomiting in acute myocardial infarction to location of the infarct.

To determine whether the incidence of nausea and vomiting in patients with acute myocardial infarction (AMI) varies with infarct location, we studied 180 patients who had been admitted to our hospital for ST-segment elevation AMI or AMI associated with left bundle branch block. The presenting symptoms (chest pain, nausea, and vomiting), initial electrocardiographic findings, and additional demographic, clinical, laboratory, and outcome data were extracted from the medical records and correlated with the infarct location. Of the 180 patients with AMI, 108 (60%) had inferior and 72 (40%) had anterior infarcts. Nausea was reported in almost 2/3 of all patients, and vomiting in nearly 1/3. Both nausea and vomiting showed a trend toward a greater incidence in patients with inferior than with anterior infarcts (69% vs 56% and 33% vs 26%, respectively). However, the differences were not statistically significant. In conclusion, nausea and vomiting are common presenting symptoms in patients with either inferior or anterior wall AMI, but their frequency is unrelated to the infarct location.