Dear editor: There is a favorable decreasing trend of the age-standardized mortality rates among Mexicans with lung cancer (LC)¹1. Hernández-Garduño E, Ocaña-Servín HL. Lung cancer mortality trends in Mexico, 1999-2014. Salud Publica Mex. 2018;60(3):366. https://doi.org/10.21149/8705
https://doi.org/10.21149/8705... and males with chronic obstructive pulmonary disease (COPD).²2. Hernández-Garduño E, Ocaña-Servín HL. Temporal trends in chronic obstructive pulmonary disease mortality in Mexico, 1999-2014. Int J Tuberc Lung Dis. 2017;21(3):357-62. https://doi.org/10.5588/ijtld.16.0571
https://doi.org/10.5588/ijtld.16.0571... Hospital discharge rates (HDR per 1000 total hospital discharges) trends represent another indicator of changes in LC and COPD incidence. Using joinpoint regression, this countrywide study determined HDR trends of LC and COPD in Mexicans age ≥40 years. HDR trends of other cancers (OC) and other diseases were calculated for comparison. From 2000 to 2014 the LC-HDR decreased in the whole sample (WS) and in males (annual percent change or APC= -2.3 and-3.6 respectively, p<0.05) but not in females, APC=-0.2, p=0.82. COPD-HDR’ APC decreased by -2.2, -2.9, -1.6 for the WS-males-females respectively while OC-HDR’ APC increased 3.4, 2.5 and 3.9 respectively, p<0.05 (table I).³3. Dirección General de Información en Salud. Bases de datos sobre egresos hospitalarios [sitio en internet]. México: Secretaría de Salud, 2000-2014 [citado 2018, febrero 27]. Disponible en: http://www.dgis.salud.gob.mx/contenidos/basesdedatos/std_egresoshospitalarios.html
http://www.dgis.salud.gob.mx/contenidos/...

In 2007-2008 the Seguro Popular de Salud through the program Fondo de Protección Contra Gastos Catastóficos increased funding for cancer⁴4. Aracena-Genao B, González-Robledo MC, González-Robledo LM, Palacio-Mejía LS, Nigenda-López G. Fondo de Protección contra Gastos Catastróficos. Salud Publica Mex . 2011;53(Suppl 4):407-15. https://doi.org/10.1590/S0036-36342011001000004
https://doi.org/10.1590/S0036-3634201100... which may explain the OC-HDR increase seen from 2008 to 2014 (figure 1) in WS-males-females (APC of 8.7, 5.9, and 10.0 respectively, p<0.05, data not shown).

In conclusion, LC-hospitalizations decreased in males by 2.3% annually from 2000 to 2014 while COPD hospitalizations decreased at a higher rate in males (APC -2.9) than females (APC -1.6). The main contributors for this favorable trend are likely the reduction of smoking prevalence overtime (estimated 26.2% in 1998-2002 and 21.7% in 2011)⁵5. Reynales-Shigematsu LM, Guerrero-López CM, Lazcano-Ponce E, Villatoro-Velázquez JA, Medina-Mora ME, Fleiz-Bautista C, et al. Encuesta Nacional de Adicciones 2011: Reporte de Tabaco [documento en internet]. Ciudad de México: Secretaría de Salud , 2012 [citado 2018, febrero 27]. Disponible en: http://www.conadic.salud.gob.mx/pdfs/ENA_2011_TABACO.pdf
http://www.conadic.salud.gob.mx/pdfs/ENA... and the cigarette taxes and anti-smoking laws implemented in 2007 and 2008.

The lack of statistically significant reduction in female’s COPD mortality²2. Hernández-Garduño E, Ocaña-Servín HL. Temporal trends in chronic obstructive pulmonary disease mortality in Mexico, 1999-2014. Int J Tuberc Lung Dis. 2017;21(3):357-62. https://doi.org/10.5588/ijtld.16.0571
https://doi.org/10.5588/ijtld.16.0571... and of LC hospitalizations found in this study indicate that factors other than smoking are playing a role. The prevalence of biomass smoke (BS) exposure resulting from cooking remains high in rural Mexico (45%)⁶6. Hernández-Garduño E, Gómez-García E, Campos-Gómez S. Prevalence trends of wood use as the main cooking fuel in Mexico, 1990-2013. Salud Publica Mex . 2017;59(1):68-75. https://doi.org/10.21149/7770
https://doi.org/10.21149/7770... where females are usually in charge of cooking and therefore more exposed to BS and have also a higher risk of lung cancer.⁷7. Hernández-Garduño E, Brauer M, Pérez-Neria J, Vedal S. Wood smoke exposure and lung adenocarcinoma in non-smoking Mexican women. Int J Tuberc Lung Dis . 2004;8(3):377-83. Future studies should be focused on factors including genetic susceptibility or the degree of exposure to BS/occupational agents

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