Publications

In terms of population attributable risk, about 48% of all myocardial infarctions in young and middle aged Italian women were attributable to cigarette smoking, which is therefore by far the most important preventable determinant of the disease.

To the Editor: Rates of spontaneous abortion increased in Italy from 6.3/100 pregnancies in 1980 to 7.6 in 1991. The increase was generally constant during the period and was similar across subsequent age strata, with the exception of teenagers and of women age 50 or more. 1 We have now updated trends in rates of spontaneous abortion to 1995, using data published annually by the Italian National Institute of Statistics (ISTAT). 2,3 In Italy, spontaneous abortion is defined by law as a termination of pregnancy 180 days or less after the last menstrual period. The spontaneous abortion rate has been calculated using the number of spontaneous abortions (SA) as numerator and the total number of pregnancies (ie, the simple sum of spontaneous and induced abortions (IA) plus births (LB)) as denominator. Rates according to maternal age have been also analyzed using direct standardization for maternal age, taking the Italian population of 1982 as reference. 4 Because spontaneous abortion and induced abortion are competing risks, we have also analyzed the data using the statistic: SA/(SA+LB+IA/2). 5 Overall, age-adjusted rates of spontaneous abortion increased from 7.3 in 1992 to 8.3/100 pregnancies in 1995 with 95% confidence intervals of 7.2–7.5 and 8.2–8.4, respectively (Table 1).Similar trends also emerged after considering the competitive role of induced abortion. The increase in the rate of spontaneous abortion was larger in very young (<15 year, from 21.2 to 31.1/100 pregnancies, in 1992 and 1995, respectively) and older (≥50 years from 36.8 to 40.4/100 pregnancies) women, but we also found some increased risk in the intermediate age groups (Table 2).These trends in spontaneous abortions can be explained by improved diagnosis, following a wider availability of transvaginal ultrasounds, but this explanation cannot account for the different trends in various strata of age. It is also likely that the criteria for definition at certification of spontaneous abortion have changed in clinical practice over the last few years. We have not considered ectopic pregnancies, but this omission should not have introduced any marked bias. Table 1: Trends of Crude and Standardized for Age Rate of Spontaneous Abortion in Italy, 1982, 1990–1995Table 2: Trends of Spontaneous Abortion (Rates per 100 Pregnancies) According to Maternal Age (Italy, Selected Years)An increased frequency of abortion has been observed in pregnancies after assisted reproduction 6 and also after amniocentesis performed in the first trimester of pregnancy. 7 These effects could explain the increased rates of spontaneous abortion in women 35 years of age or older, but not in younger women. Whereas the rate of pregnancy (ie, the number of SA plus IA and births on number of women) for very young girls (<15 years) remained stable from 1981 to 1995, spontaneous and induced abortions had an inverse trend. 8 This pattern could be explained by a greater attention on sex education of teenagers in the 1990s, with a rise of wanted pregnancies and a simultaneous diminution of IA. These trends could have affected the rate of SA, resulting in an increase of the proportion of IA that could potentially end in SA. Cristina Rozzi Luigi Benassi Fabio Parazzini Liliane Chatenoud Carlo La Vecchia Guido Benzi

Self-reported smoking prevalence is decreasing in men but not in females. There is widespread support for smoking restriction in public areas.

Apparent differences in the adoption of the Dietary Approach to Stop Hypertension (DASH) diet have been reported between less and more educated individuals. However, the mediating role of income has not been clarified. In this study, we aimed at quantifying the mediating effect of income on the relationship between education and the DASH score in the UK population. We analysed data on 4864 subjects aged 18 years and older collected in three waves of the National Diet and Nutrition Survey (2008-2016). The DASH score was calculated using sex-specific quintiles of DASH items. We carried out a counterfactual-based mediation analysis to decompose the total effect of education on DASH score into average direct effect and average causal mediation effect mediated by income. We found that the overall mediating effect of income on the relationship between education and the DASH score was only partial, with an estimated proportion mediated ranging between 6 and 9 %. The mediating effect was higher among females (11·6 %) and younger people (17·9 %). Further research is needed to investigate which other factors may explain the socio-economic inequality in the adoption of the DASH diet in the UK.

We thank Dr. Grant for his interest in our work.1 We cannot make inference on latitude of exposure, specifically, on latitudes south of about 40°. The subjects diagnosed with skin cancer are most likely, than those without skin cancer, to have been heavily exposed to sun in this Swiss population. Exposure may have occurred in the country with mountainous areas, where sun irradiation is stronger than at sea level,2, 3 or abroad. With reference to smoking, according to the Monograph 83 of the International Agency for Research on Cancer,4 there is evidence suggesting the lack of carcinogenicity of tobacco smoking for female breast cancer. There is clear evidence for the risk of neither prostate cancer nor skin cancer. There is some evidence from prospective cohort and case-control studies that the risk of colorectal cancer is increased among tobacco smokers. However, it is not possible to conclude that the association between tobacco smoking and colorectal cancer is causal (abstracted from reference4, pp. 1183–86). It is, therefore, unlikely that smoking has introduced any major bias, confounding, or modifying effect in the results of our study. The evidence from population-based cohort studies like ours1, 5-7 is open to criticism, but is in any case more valid than that of correlation (ecologic) ones often quoted by Dr. Grant in support of his views. Dr. Soerjomataram and Dr. de Vries suggest to provide additional information to address the issue of surveillance bias and stratified or sub-group analysis in our study.1 Although we caution toward inference based on subgroups, we are glad to provide the information requested, when available. With reference to potential surveillance bias, the number of male skin cancer cases in Vaud and Neuchatel, Switzerland were 15,246 when compared with 13,541 in the Dutch study, and that of population years at risk was 109,176. There is no reason to suppose that inclusion—rather than exclusion—of early prostate cancer introduces selection bias. In the mid 1990's, about 10% of men aged 65 or over may have undergone prostate-specific antigen (PSA) testing in Vaud and Neuchatel,8 and this proportion has risen over more recent years, in the absence, however, of any organised screening programme. The standardised incidence ratio (SIR) of prostate cancer was 1.18 (95% confidence interval (CI): 0.93–1.47) in the first, 1.24 (95% CI: 0.97–1.57) in the second, 1.16 (95% CI: 0.88–1.49) in the third year after diagnosis of skin cancer, and 1.13 (95% CI: 1.02–1.25) in subsequent years. Corresponding values were 1.34, 1.06, 0.89, 1.08 for colorectal, and 1.07, 1.20, 1.09, 1.06 for breast cancer. This weighs against the hypothesis of an early reduction in risk, which levels off with time, due to potentially reduced sunshine exposure after skin cancer diagnosis. With reference to strata of sex, the SIR of colorectal cancer were 1.06 (95% CI: 0.94–1.19) in men, and 1.14 (95% CI: 1.00–1.30) in women. The estimates were not significantly heterogeneous across sexes. We have information on stage and grade of prostate cancer only for recent years; thus numbers of subsequent cancers are inadequate now for any inference. Thus, none of the additional or subgroup analyses indicated by Dr. Soerjomataram and Dr. de Vries modify our conclusion that incidence of colorectal, breast, and prostate cancers is not reduced in patients diagnosed with skin cancer. We agree with Dr. Soerjomataram and Dr. de Vries that collaborative studies would help clarify the issue, and provide acceptable statistical power for subgroup analyses. Dr. Robert Tarone, from the International Epidemiology Institute, Rockville, MD, USA, kindly pointed to us that the expected rates in Table I were smaller than those in Table II.1 The correct Table I is, therefore, enclosed below. The first paragraph of the results section consequently reads as follows: “Table 1 gives the numbers of observed and expected cancers of the prostate, breast, and colorectum following basal and squamous cell skin cancers, skin melanomas, and all skin cancers combined. Overall, 680 prostate cancers were observed vs. 593.4 expected (SIR = 1.15; 95% CI: 1.06–1.24), 440 breast cancers were observed vs. 402.3 expected (SIR = 1.09; 95% CI: 0.99–1.20), and 535 colorectal cancers were observed vs. 488.0 expected (SIR = 1.10; 95% CI: 1.01–1.19). We, also, considered the risk of prostate, breast, and colorectal cancers in separate strata of age at diagnosis, location (head and neck vs. other), and time since skin cancer diagnosis, but found no indication of reduced risk in any of the strata considered, most SIRs for prostate, breast, and colorectal cancers being around or slightly above unity. The SIRs of colorectal cancer were 1.06 (95% CI: 0.94–1.19) for men, based on 292 observed vs. 275.4 expected, and 1.14 (95% CI: 1.00–1.30) for women, based on 243 vs. 212.6 expected.” These changes do not modify the inference and conclusions of our work. We apologize, nonetheless, the readers for the correction, and again thank Dr. Tarone for his careful reading and valuable help. Yours sincerely, Fabio Levi, Lalao Randimbison, Van-Cong Te, Manuela Maspoli Conconi, Carlo La Vecchia