Age-period-cohort effect on mortality from cervical cancer

Meira, Karina Cardoso; Silva, Gulnar Azevedo e; Silva, Cosme Marcelo Furtado Passos da; Valente, Joaquim Gonçalves

doi:10.1590/S0034-8910.2013047004253

OBJECTIVE

To estimate the effect of age, period and birth cohort on mortality from cancer of the cervix.

METHODS

Mortality data for cervical cancer in women aged over 30, between1980 and 2009, for the municipalities of Rio de Janeiro and Sao Paulo, Southeastern Brazil,were extracted from the Mortality Information System. The estimated annual percentage change was calculated for the periods 1980-1994 and 1995-2009. Age, period and cohort effects were assessed employing the Poisson regression model, using estimated functions, deviations, curvatures and drift through the library Epi statistical program R version 2.7.2.

RESULTS

The average mortality rate per 100,000 women for the period in Rio de Janeiro was 15.90 and 15.87 in Sao Paulo. There was a significant reduction in mortality from cervical cancer in the two periods (1980-1994 and 1995-2009) in both Rio de Janeiro, -1.20% (95%CI -2.20;-0.09) -1.46% (95%CI -2.30;0.61) and in Sao Paulo, -2.58% (95%CI -3.41;1.76) and -3.30% (95%CI -4.30;2.29). The analysis of effects of curvature indicated reduction in deaths in successive cohorts (RR < 1 in women born after the 1960s). There was marked reduction in relative risk (RR) from the 2000s onwards.

CONCLUSIONS

The study showed that, in the time period analyzed, the period had an effect on the reduction in mortality rates for cervical cancer, bearing in mind that there was a protective effect (RR < 1) from the year 2000 onwards and in women born after the 1960s

Uterine Cervical Neoplasms, mortality ; Cohort Effect ; Period Effect ; Age Effect ; Logistic Models

[1] The authors declare that there are no conflicts of interests.

Age group (years)	Rio de Janeiro
Age group (years)	1980 to 1984	1985 to 1989	1990 to 1994	1995 to 1999	2000 to 2004	2005 to 2009

30 to 34	3.60	4.24	3.60	3.31	3.46	3.21
35 to 39	6.91	6.21	9.29	7.40	5.00	6.02
40 to 44	11.20	8.37	9.31	10.40	9.54	9.64
45 to 49	17.99	13.05	16.51	14.14	16.15	12.78
50 to 54	19.53	21.63	22.25	18.40	17.87	12.78
55 to 59	20.40	26.02	23.66	21.13	17.57	15.09
60 to 64	29.38	22.14	25.25	29.05	21.82	17.28
65 to 69	34.64	28.57	31.99	24.60	25.43	22.03
70 to 74	26.76	18.51	18.37	16.70	17.01	17.62
75 +	31.25	23.41	21.05	30.71	22.02	15.21
Rate^a	17.16	15.03	16.23	15.29	13.78	11.70

Age group (years)	Sao Paulo
Age group (years)	1980 to 1984	1985 to 1989	1990 to 1994	1995 to 1999	2000 to 2004	2005 to 2009

30 to 34	2.98	3.18	2.58	2.38	2.25	2.37
35 to 39	6.43	5.27	4.69	5.21	4.58	3.79
40 to 44	12.80	9.54	9.03	9.77	7.93	8.10
45 to 49	15.32	14.33	17.45	14.44	12.65	10.32
50 to 54	22.61	18.80	21.05	19.67	16.46	12.23
55 to 59	30.55	23.43	25.04	23.20	21.54	16.94
60 to 64	35.26	28.26	22.88	20.83	22.84	16.31
65 to 69	36.41	30.51	30.76	31.25	25.56	20.21
70 to 74	25.78	24.80	24.67	28.65	22.41	25.55
75 +	24.45	24.87	24.68	29.74	22.83	20.30
Rate^a	18,43	15,58	15,69	15,36	13,44	11,68

Age group (years)	Rio de Janeiro
Age group (years)	1980 to 1994		1995 to 2009

	EAPC%	95%CI	EAPC%	95%CI
30 to 34	1.73	-3.90;7.70	-0.29	-3.98;3.54
35 to 39	1.55	-3.00;6.30	-4.85	-9.76;0.33
40 to 44	-14.09	-54.34;61.64	-1.08	-3.07;0.96
45 to 49	-0.99	-4.77;2.93	0.46	-1.74;2.70
50 to 54	0.12	-2.46;2.77	-0.30	-3.82;3.35
55 to 59	1.44	-1.69;4.67	-0.82	-2.80;1.20
60 to 64	-1.82	-3.90;0.30	-5.39^a	-7.15;-3.60
65 to 69	-1.58	-5.41;2.41	-1.67	-5.16;1.95
70 to 74	-2.85	-6.69;1.14	-3.10	-6.19;0.09
75 +	-3.60^a	-5.13;-2.05-	-7.36^a	-9.21;-5.48
Annual	-1.20^a	-2.29;-0.09	-2.58^a	-3.41;-1.76

Age group (years)	Sao Paulo
Age group (years)	1980 to 1994		1995 to 2009

	EAPC%	95%CI	EAPC%	95%CI
30 to 34	-1.03	-4.48;2.55	0.51	-2.78;3.90
35 to 39	-3.19	-7.34;1.14	-3.51^a	-6.62;-0.29
40 to 44	-3.40^a	-5.21;-1.55	-1.64	-3.67;0.43
45 to 49	2.24	-1.68;6.33	-2.87^a	-5.33;-0.35
50 to 54	-0.81	-3.53;1.99	-4.14^a	-5.67;-2.59
55 to 59	-2.39^a	-4.60;-0.13	-2.11	-4.33;0.16
60 to 64	-3.86^a	-5.77;-1.91	-2.12	-4.40;0.22
65 to 69	-1.76	-3.57;0.08	-3.83^a	-6.12;-1.48
70 to 74	-0.66	-3.36;2.11	-4.83^a	-7.41;-2.19
75 +	0.15	-2.80;3.19	-4.61^a	-7.09;-2.06
Annual	-1.46^a	2.30;-0.61	-3.30^a	-4.30;-2.29