Table 3

Characteristics associated with overestimation of mammography screening efficacy among 639 women of ages 40 to 80 years who stated that mammography screening prevents deaths attributable to breast cancer (Geneva, Switzerland)^3-150

Characteristic		Estimated proportion of death from breast cancer prevented by mammography screening		p Value
		One quarter or more Number			One half or more (overestimate)
		One quarter or more Number			Number	Raw %
Overall	639	466	72.9
Pros (approximate tertiles)				<0.001^3-152
Lowest	213	140	65.7
Middle	186	136	73.1
Highest	234	188	80.3
Cons (approximate tertiles)				<0.001^3-152
Lowest	262	215	82.1
Middle	215	149	69.3
Highest	157	99	63.1
Reluctant to pay Swiss Fr 200 for a mammogram^3-153 ^3-154				0.03
Yes	67	43	64.2
No	497	379	76.3
Perceived an organised programme of mammography screening as useful for themselves				0.18
Yes	495	367	74.1
No	101	68	67.3
Intended to have a mammogram in the future				<0.001
Yes	458	353	77.1
No	144	89	61.8
First degree relative with breast cancer				0.40
Yes	48	38	79.2
No	591	428	72.4
Subjective risk of breast cancer as compared with other women				0.002
Lower	96	68	70.8
Similar	330	241	73.0
Higher	47	44	93.6
No opinion	154	103	66.9
Have had a mammogram in the past two years				0.29
Yes	326	244	74.8
No	313	222	70.9
Visit to a gynaecologist during the past year				0.35
Yes	506	375	74.1
No	84	58	69.0
Mammography recommended by a gynaecologist during the past two years				1.0
Yes	339	253	74.6
No	258	193	74.8
Age (y)				0.15
40–49	204	150	73.5
50–69	371	276	74.4
70–80	64	40	62.5
Married				0.93
Yes	411	300	73.0
No	223	164	73.5
Citizenship				<0.001
Swiss	487	373	76.6
Other	149	92	61.7
Education level (y)				0.12
⩽10	166	114	68.7
>10	440	331	75.2
Monthly net income per person (Swiss Fr)^3-154				0.39
⩽1500	114	82	71.9
>1500	415	316	76.1

↵3-150 Analysis restricted to women who stated that mammography screening prevent about one quater (realistic estimators), or about one half or three fourths of deaths attributable to breast cancer in women over age 50 (overestimators).
3-151 As a result of missing data, numbers may sum to less than 639.
↵3-152 χ² test of linear trend.
↵3-153 Amount charged for a screening mammogram in Geneva.
↵3-154 In December 2000, 1 Swiss Fr was equal to £0.40.