水中毒と気象との関係について

Relationship between Water Intoxication and Weather

抄録

　約4年間に一精神科病院で3,776回の血清Na検査が行われた。糖尿病などの症例を除いた3,437の検体について，前々日，前日，当日の天気，最高気温，最低気温，気圧，湿度，露点温度を調べた。軽度から重度の低Na群では，3日間の最低気温が対照群に比べて有意に高かった(p＜0.05)。重度低Na群は，その他に，対照群と比べて当日の湿度が有意に高く(p＜0.01)，気圧が有意に低かった(p＜0.01)。中等度から重度の低Na群の血清Na値と当日の湿度との間に負の相関関係が認められた(r＝-0.287，p＝0.028)。また，重度低Na群の中の水中毒群4例は，無症状群4例に比べて気象の影響が強く認められた。天気の悪さ，湿度の高さなどの気象状況が水中毒の発症に関与していると考えられた。

　A total of 3,776 samples were tested for serum sodium concentration in a particular psychiatric hospital over an approximately 4-year-long-period. Samples collected from diabetic patients were not included in this study. Meteorological parameters such as weather conditions, maximum and minimun temperatures, atmospheric pressure, humidity, and dew-point temperatures were examined 1 and 2 days before the test and on the day of the test in the case 3,437 samples. The minimum temperatures during this 3-day period were significantly higher in the case of patients with mild to severe reduction in sodium levels than those in the case of the control group (p＜0.05). Humidity was significantly higher (p＜0.01), and atmospheric pressure (p＜0.01) was significantly lower in the severely low sodium group than in the control group. In the moderately and severely low sodium groups, there was a negative correlation between the serum sodium level and the humidity on the day of the test (r＝－0.287, p＝0.028). Four patients with water intoxication in the severely low sodium group were affected by the meteorological parameters to a greater extent than the 4 asymptomatic patients. Meteorological factors such as bad weather conditions and high humidity were considered to be involved in the onset of water intoxication.