Table 3.

 Number needed to treat to cause one additional lymphoma per year

Age (y)	Lymphoma incidence*	NNH if relative risk of lymphoma = 2	NNH if relative risk of lymphoma = 4	NNH if relative risk of lymphoma = 6
20–29	7.65	13072	4357	2614
30–39	10.70	9346	3115	1869
40–49	16.60	6024	2008	1205
50–59	29.60	3378	1126	676
60–69	56.45	1771	591	354
70–79	93.90	1065	355	213

*Incidence rates per 100 000 person years from 1996–2000 (SEER data¹⁷).

NNH, number needed to harm one additional patient per year.