Table 3.

Comparison of questionnaire data on tea temperature among 300 cases with oesophageal squamous cell carcinoma and 571 matched controls, in Golestan, northern Iran, 2003-7

Interval (minutes)*	Tea temperature			Weighted κ statistics (SE)	Correlation coefficient† (P value)
	Warm or lukewarm	Hot	Very hot
≥4	454	65	7	0.68 (0.03)	0.69 (<0.001)
2-3	57	163	30
<2	8	35	45

Because of missing data and one participant who did not drink tea, numbers add up to 864 rather than 871.

*Interval between tea being poured and drunk.

†Spearman’s rank correlation coefficient.