NPNisha I. Parikh

Nisha I. Parikh

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Previous Organizations / Institutes

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Nisha I. Parikh has a total of 36 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Facing a Tsunami

    by Shannon L. Walker, Nicky J. Mehtani, Nisha I. Parikh


  • Open Access

    Effects of reproductive period duration and number of pregnancies on midlife ECG indices: a secondary analysis from the Women’s Health Initiative Clinical Trial

    by Nisha I Parikh, Kristopher Kapphahn, Haley Hedlin, Jeffrey E Olgin, Matthew A Allison, Jared W Magnani, Kelli R Ryckman, Molly E Waring, Marco Valentin Perez, Barbara V Howard

    Objectives: Pregnancy, menses and menopause are related to fluctuations in endogenous sex hormones in women, which cumulatively may alter cardiac electrical conduction. Therefore, we sought to study the association between number of pregnancies and reproductive period duration (RD, time from menarche to menopause) with ECG intervals in the Women’s Health Initiative Clinical Trials. Design: Secondary analysis of multicentre clinical trial. Setting: USA. Primary outcome measures: ECGintervals: PR interval, P-wave duration, P-wave dispersion, QTc interval. Participants: n=40 687 women (mean age=62 years) participating in the Women’s Health Initiative Clinical Trials. 82.5% were white, 9.3% black, 4% Hispanic and 2.7% Asian. Methods: In primary analysis, we employed multivariable linear regression models relating number of pregnancies and RD with millisecond changes in intervals from enrolment ECG. We studied effect modification by hormone therapy use. Results: Among participants, 5+ live births versus 0 prior pregnancies was associated with a 1.32 ms increase in PR interval (95% CI 0.25 to 2.38), with a graded association with longer QTc interval (ms) (none (prior pregnancy, no live births)=0.66 (–0.56 to 1.88), 1=0.15 (–0.71 to 1.02), 2–4=0.25 (–0.43 to 0.94) and 5+ live births=1.15 (0.33 to 1.98), p=0.008). RD was associated with longer PR interval and maximum P-wave duration (but not P-wave dispersion) among never users of hormone therapy: (PR (ms) per additional RD year: 0.10 (0.04 to 0.16); higher P-wave duration (ms): 0.09 (0.06 to 0.12)). For every year increase in reproductive period, QTc decreased by 0.04 ms (−0.07 to –0.01). Conclusions: An increasing number of live births is related to increased and RD to decreased ventricular repolarisation time. Both grand multiparity and longer RD are related to increased atrial conduction time. Reproductive factors that alter midlife cardiac electrical conduction system remodelling in women may modestly influence cardiovascular disease risk in later life. Trial registration number: NCT00000611 ; Post-results.


  • Reproductive Risk Factors and Coronary Heart Disease in the Women’s Health Initiative Observational Study

    by Nisha I. Parikh, Rebecca P. Jeppson, Jeffrey S. Berger, Charles B. Eaton, Candyce H. Kroenke, Erin S. LeBlanc, Cora E. Lewis, Eric B. Loucks, Donna R. Parker, Eileen Rillamas-Sun, et al.

    Background—: Reproductive factors provide an early window into a woman’s coronary heart disease (CHD) risk; however, their contribution to CHD risk stratification is uncertain. Methods and Results—: In the Women’s Health Initiative Observational Study, we constructed Cox proportional hazards models for CHD including age, pregnancy status, number of live births, age at menarche, menstrual irregularity, age at first birth, stillbirths, miscarriages, infertility ≥1 year, infertility cause, and breastfeeding. We next added each candidate reproductive factor to an established CHD risk factor model. A final model was then constructed with significant reproductive factors added to established CHD risk factors. Improvement in C statistic, net reclassification index (or net reclassification index with risk categories of P P =0.18); and, for women without events, net reclassification was marginally improved (net reclassification index nonevents, 0.002; P =0.04) Conclusions—: Key reproductive factors are associated with CHD independently of established CHD risk factors, very modestly improve model discrimination, and do not materially improve net reclassification.


  • Feasibility and potential role of ferumoxytol-enhanced neuroimaging in HIV-associated neurocognitive disorder

    by Beau K. Nakamoto, Cecilia M. Shikuma, Debra Ogata-Arakaki, Tracie Umaki, Edward A. Neuwelt, Bruce T. Shiramizu, Dominic C. Chow, Nisha I. Parikh, Kalpana J. Kallianpur, Bronwyn E. Hamilton

    We assessed ferumoxytol-enhanced brain MRI to identify monocyte/macrophage accumulation in HIV-associated neurocognitive disorder (HAND). Four HIV-infected subjects with undetectable HIV RNA levels on antiretroviral therapy, HIV DNA level in CD14+ cells ≥10 copies/106 cells, and cognitive impairment underwent ferumoxytol-enhanced brain MRI. On post-ferumoxytol susceptibility-weighted images, all HIV-infected subjects demonstrated a diffuse “tram track” appearance in the perivascular regions of cortical and deep white matter vessels suggesting ferumoxytol uptake in monocytes/macrophages. This finding was not present in an HIV-seronegative control. While ferumoxytol may have potential as an imaging biomarker for monocyte/macrophage accumulation in patients with HAND, future study is needed.