Major research interests:
1. Nephrolithiasis: risk factors, genetics, metabolomics and prevention
2. Chronic kidney disease: risk factors
3. Hearing loss: risk factors and prevention
4. Tinnitus: risk factors and prevention
5. Hypertension: risk factors and prevention
6. Shingles: risk factors and long-term adverse health consequences
My research has examined the epidemiology of a variety of chronic diseases including nephrolithiasis, hearing loss, analgesic nephropathy, CKD, hypertension, hypertensive disorders of pregnancy. I have recently begun studying new areas, including shingles and tinnitus.
Nephrolithiasis: risk factors and prevention
I am studying the epidemiology of nephrolithiasis in three large, prospective cohort studies: Health Professionals Follow-up Study (n=51,000 men), Nurses’ Health Study I (n=121,000 women) and Nurses’ Health Study II (n=116,000 women). In particular, I am examining the role of dietary and non-dietary factors in kidney stone formation. We have also collected more than 6000 24-hour urine samples from participants. We have an NIH grant to study metabolomics and the microbiome in individuals with and without kidney stones. The focus of this effort it to understand the etiology of stone formation and to develop new strategies to reduce stone recurrence.
Hearing loss and tinnitus
We are examining modifiable risk factors for hearing loss and tinnitus in three large cohorts (HPFS, NHS I, and NHS II). We define hearing loss in two ways: a) based on responses to the main questionnaire and a detailed supplementary questionnaire; b) formal audiometry in 3749 NHS II participants. Our work to date suggests that regular use of over-the-counter analgesics is associated with an increased risk of hearing loss, particularly in younger individuals. Dietary factors, vitamins, body size, physical activity, menopause and post-menopausal hormone use are also associated with hearing loss. We have NIH funding to examine the genetics of hearing loss and gene-environment interactions. We reported on the epidemiology of tinnitus using NHANES data. Also, in contrast to previous belief, we found in a prospective study that higher caffeine intake is associated with a lower risk of developing tinnitus.
Hypertension: risk factors and prevention
We have identified important novel risk factors for hypertension that have implications for reducing the public health burden of hypertension. For example, analgesics increase the risk of hypertension and higher intake of folate and adequate vitamin D levels each appear to reduce the risk of hypertension. Higher serum uric acid increases risk, even when values are in the ‘normal’ range. We dispelled the notion that frequent consumption of coffee or other caffeinated beverages raises the risk of hypertension. Recent work revealed that patients with primary aldosteronism treated with mineralcorticoid receptor antagonist therapy have a significantly higher risk for incident cardiometabolic events and death, independent of blood pressure control, than for patients with essential hypertension. The findings suggest that titration of MR antagonist therapy to raise renin might mitigate this excess risk.
My major teaching activities have centered on mentoring (I have a K24 award from NIDDK) and the HSPH/BWH Program in Clinical Effectiveness.