夜尿的定義是指睡著後起床小便兩次以上。這是個常發生在年長者，並且會嚴重影響睡眠品質的問題。根據美國National Health and Nutrition Examination Survey(NHANES)資料庫的統計顯示，在美國，1988-1994年間夜尿發生率為女性20.9%，男性15.5%。2005-2012年間女性發生率增加到34.9%，而男性則是30.5%。發生率增加或與社會邁向高齡化有關。很多原因會造成夜尿，但最終都引起夜間尿量增加，膀胱容量減少，及睡眠障礙。除了影響生活品質，夜尿也會增加1.2倍跌倒、1.3倍骨折及1.3倍死亡等風險。夜尿還可能依些內科慢性病如糖尿病，肥胖，和高血壓等疾病的危險因子。然而，夜尿與心血管疾病(cardiovascular disease, CVD)的相關性尚未明確，故作者使用NHANES資料庫來探討其相關性。

NHANES是由美國疾管局(United States Centers for Disease Control and Prevention, CDC)所主導，收錄美國有接受健康/營養問卷或理學/實驗室檢查的居民。本實驗收錄2005-2012年的病患資料，40790人中共採用14114人的資料進入分析統計。夜尿的定義為夜間兩次以上小便，其中2~4次為輕微夜尿，4次以上為嚴重夜尿。心血管疾病(CVD)的定義則是病患使用降血壓藥物，抗血小板藥物，抗凝血劑，以及任何下述症狀:醫師告知有罹患心衰竭/冠心症/心肌梗塞/心絞痛等任一疾病。

在收錄的14114位病患中，男性6888人，女性7226人，平均年齡52.6歲。其中一共有1622位罹患CVD (11.5%).。4610病患有夜尿(32.7%)，其中男性的發生率是 30.6%而女性35.2%.CVD在年長者，肥胖(BMI指數較高)者，抽菸者，或是患有糖尿病、高血壓、高血脂的病患發生率較高。而患有CVD的病患其夜尿發生比率也較高。在多變項分析中，表現輕微或嚴重夜尿的病患其得到CVD的勝算比(odds ratio, ORs)分別為1.23(95% CI: 1.08–1.39; p = 0.002)和1.74(95% CI: 1.39–2.17; p < 0.001)。用propensity score matching(PSM)後，輕微或嚴重夜尿病患其得到CVD的ORs分別為1.27(95% CI: 1.10–1.48; p = 0.001)和1.73(95% CI:1.33–2.26; p < 0.001)。

雖然夜尿與CVD直接的致病機轉仍未定論，但有些研究認為血壓高/心衰竭，會拉伸(stretching)心肌細胞，增加釋放心房排鈉胜肽(atrial natriuretic peptide, ANP) 而引起利鈉和利尿。這機轉可能造成夜間多尿(nocturnal polyuria)，而夜間多尿造成睡眠中斷會進一步導致血壓上升而形成惡性循環。本篇文章為資料庫回溯性研究，無法得知每位病患三天的24小時排尿日記，因此無法區別夜尿特性，然而本邊所得到的結論依舊能提醒我們，若遇到夜尿患者，應衛教夜尿可能帶來的心血管疾病風險，且夜尿次數越多與心血管疾病相關性越高，在治療夜尿的同時，也應積極檢查並控制潛在的心血管疾患，如此才能「治標」又「治本」。

Aims: To investigate the association of nocturia with the prevalence of cardiovascular disease (CVD) using the National Health and Nutrition Examination Survey (NHANES) data.

Methods: Among the 40 790 individuals who participated in NHANES from 2005 to 2012, 14 114 adults were analyzed in this study. A participant was considered to have nocturia if they have two or more voiding episodes nightly. In addition, participants with nocturia more than four times in a day were considered to have severe nocturia. A multivariate logistic regression analysis with adjustment for confounding variables, including age, sex, race, body mass index (BMI), smoking status, alcohol consumption, sleeping time, dyslipidemia, hypertension, and diabetes mellitus was performed with 1:1 propensity score matching (PSM).

Results: Nocturia occurred in 4610 individuals (32.7%). The prevalence of CVD was significantly higher in men, older individuals, 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. Multivariate analysis showed that odds ratios (ORs) of mild and severe nocturia for CVD were 1.23 (95% confidence interval [CI]: 1.08–1.39) and 1.74 (95% CI: 1.39–2.17), respectively. After 1:1 PSM, the ORs of mild and severe nocturia were 1.27 (95% CI: 1.10–1.48) and 1.73 (95% CI: 1.33–2.26), respectively, showing statistical significance.

Conclusion: Data from the NHANES indicate that CVD was significantly associated with the prevalence of nocturia, after taking major confounding factors into account. Furthermore, the risk for CVD increases with increasing nocturia severity.