Seasonal variation in the onset of acute pancreatitis

Table 3 Seasonal variation of acute pancreatitis (chronobiologic parameters by Fourier analysis)

	n	Period (h)	PR (%)	MESOR	Amplitude	Peak	95%CL	P
Total	549	8766	51.1			March	February-April	0.006
		4383	33.7			September	August-October	0.017
		Overall	84.8	45.68	3.28	March	February-April	0.005
Males	285	8766	42.6			March	February-April	0.030
		4383	32.7			September	NS	0.052
		Overall	75.4	23.71	9.06	March	February-April	0.027
Females	264	8766	50.9			March	February-April	0.024
		4383	22.3			September	NS	0.121
		Overall	73.3	21.97	4.52	March	February-April	0.035
Biliary tract disease	286	8766	42.2			March	NS	0.074
		4383	19.5			August	NS	0.234
		Overall	61.8	23.72	7.60	March	NS	0.108
No bil. tract disease	263	8766	44.8			March	February-April	0.041
		4383	25.1			October	NS	0.119
		Overall	69.9	21.96	7.66	March	NS	0.052
Chronic alcoholism	48	8766	13.2			March	NS	0.415
		4383	40.7			September	NS	0.109
		Overall	53.9	3.91	2.51	March	NS	0.192
Fatal cases	18	8766	86.2			November	November-December	< 0.001
		4383	10.9			June	May-July	0.004
		Overall	97.1	1.50	1.90	November	November-December	< 0.001

PR = percentage of rhythm (percentage of overall variability of data about arithmetic mean attributable to the rhythmic fitted function MESOR = midline estimated statistics of rhythm, the rhythm-adjusted mean over the time period analysed amplitude: half the distance between the absolute maximum and minimum of the function of the best-fitting curve 95%CL = 95% confidence limits NS = not significant, (when acrophase did not reach the significance level, 95%CL could not be given).