Nocturia is highly prevalent and one of the most distressing lower urinary tract symptoms among older adults. However, the pathophysiology of nocturia is variable and difficult to confirm. In addition, to our knowledge, there is no literature to date that has analyzed their association using a nationally representative population-based database such as the National Health and Nutrition Examination Survey (NHANES) studies of the United States. Therefore, we investigated the association and influence of nocturia on the prevalence of cardiovascular disease (CVD) using the NHANES data.

NHANES is operated continuously in two-year cycles conducted by the US Centers for Disease Control and Prevention (CDC), which is a cross-sectional study in which participants were sampled to represent populations living in the United States and underwent health and nutrition surveys as well as physical and laboratory tests. All protocols were approved by the Research Ethics Review Board of the National Center for Health Statistics, US Centers for Disease Control and Prevention. Among the 40,790 individuals who participated in NHANES from 2005 to 2012, only 14,365 adults were analyzed in this study.
A participant was considered to have nocturia if they answered “two or more” of the following questions: “During the past 30 days, how many times per night did you most typically get up to urinate, from the time you went to bed at night until the time you got up in the morning?” A participant was considered to have CVD if they answered yes to ≥1 of the following structured questionnaire: “Has a doctor ever told you that you had congestive heart failure?”, “Has a doctor ever told you that you had coronary heart disease?”, “Has a doctor ever told you that you had a heart attack (or myocardial infarction)?”, or “Has a doctor ever told you that you had angina pectoris?”
A multivariate logistic regression analysis with adjustment for confounding variables, including age, sex, race, body mass index, smoking status, dyslipidemia, hypertension, and diabetes mellitus was performed with 1: 1 propensity score matching (PSM) for the confounding variables, taking into consideration heterogeneity of demographic characteristics according to CVD.

A total of 14,365 adults (7,023 men, 7,342 women, mean age 52.6 years) aged 20-85 years were included in the study. There were 1,873 CVD cases (13%). Nocturia occurred in 4,727 individuals (32.9%), and the prevalence according to sex was 30.6% in men and 35.2% in women. The presence of CVD was more common in the elderly, men, those with higher BMI, smokers, and those with diabetes, hypertension, and hyperlipidemia. There was also a significantly higher prevalence of nocturia in the participants with CVD. In the multivariate analysis, the odds ratios (ORs) of mild and severe nocturia for CVD were 1.259 (95% CI, 1.12-1.417, p <0.001) and 1.996 (95% CI, 1.627-2.449, p <0.001), respectively. Taking into account the heterogeneity of participants with CVD, additional analysis was performed using 1:1 PSM. Although there was little heterogeneity of other confounding variables due to CVD, the ORs of mild and severe nocturia were 1.221 (95% CI, 1.064-1.401, p = 0.004) and 1.833 (95% CI, 1.431-2.347, p <0.001), respectively, showing maintained statistical significance.

The present nationally representative population-based study demonstrated that CVD was significantly associated with the prevalence of mild (two to three times per night)-to-severe (four or more than four times per night) nocturia in men and women after taking major confounding factors into account. In addition, in a well-balanced PSM data, our study showed that CVD was associated with prevalence of nocturia.

These findings indicate that nocturia may predict CVD as the number of nocturia increases. Moreover, the results provide better understanding of the underlying mechanisms of nocturia and the association between nocturia and CVD.