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We study nonparametric likelihood-based estimators of the mean function of counting processes with panel count data using monotone polynomial splines. The generalized Rosen algorithm, proposed by Zhang & Jamshidian (2004), is used to compute the estimators. We show that the proposed spline likelihood-based estimators are consistent and that their rate of convergence can be faster than n 1/3. Simulation studies with moderate samples show that the estimators have smaller variances and mean squared errors than their alternatives proposed by Wellner & Zhang (2000). A real example from a bladder tumour clinical trial is used to illustrate this method.

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Although the PA's collections do not cover their costs, the indirect economic and patient care impacts are clear. By increasing emergency room pull through and decreasing times to Operating Room (OR), operative times, lengths of stay, and complications, their existence is clearly beneficial to hospitals, physicians, and patients as well.

Objectives: To determine whether healthy lifestyle decreases the risk of developing hypertension in pre-hypertensive patients.Study design: A longitudinal study.Setting & participants: Randomly selected pre-hypertensive young adults 20-45 years old without any vascular disease such as stroke or diabetes.Predictors: Four lifestyle factors (a body mass index [BMI] of 18.5-24.9 kg/m2, regular physical activity, no alcohol use and 6-8 h of sleep per day), individually and in combination.Outcomes: Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg, or a diastolic BP (DBP) ≥ 90 mmHg or self-reported hypertension.Measurements: Multivariate adjusted Cox proportional hazards.Results: During a median follow-up of 4.7 years, 1009 patients were enrolled in our study, and 182 patients developed hypertension. Compared with a BMI of 18.5-24.9 kg/m2, a BMI of 25-30 kg/m2 and a BMI of >30 kg/m2 were associated with an increased risk of hypertension occurrence (hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.19-2.84 and HR, 2.62; 95% CI, 1.01-6.80, respectively). Compared with sleep duration of >8 h/day, 6-8 h/day of sleep was associated with a lower risk of hypertension occurrence (HR, 0.40; 95% CI, 0.18-0.86). There were no statistically significant associations between physical activity or alcohol use and hypertension occurrence (P>0.05).Limitation: All lifestyle factors were measured only once.Conclusion: Healthy BMI (18.5-24.9 kg/m2) and sleep duration (6-8 h/day) were associated with a lower risk of the occurrence of hypertension in pre-hypertension patients.

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