The influence of lifestyle, diet, and reproductive history on age at natural menopause in Spain: Analysis from the EPIC-Spain sub-cohort.

OBJECTIVE: To determinate the role of lifestyle factors, recent diet, menstrual factors, and reproductive history in age at natural menopause in adult Spanish women. METHODS: In total, 12 562 pre-menopausal women were available for analysis from the EPIC-Spain sub-cohort. Women were recruited between 1992 and 1996 in five regions of Spain (Asturias, Granada, Murcia, Navarra, and San Sebastian) and, for these analyses, were followed for 3 years. Questionnaires on diet, lifestyle, anthropometric measurements, and reproductive and exogenous hormones history were collected at baseline. Menopause status was updated at a median of 3 years of follow-up. RESULTS: After a median of 3 years of follow-up 1166 women became postmenopausal. An earlier age at menopause was observed in current smokers (HR: 1.29; 95%CI 1.08-1.55) and in non-users of oral contraceptives (HR: 1.32; 95%CI 1.01-1.57). A later age at menopause was observed in women with irregular menses (HR: 0.71; 95%CI 0.56-0.91) and in women with a higher number of pregnancies (HR: 0.74; 95%CI 0.56-0.94). CONCLUSIONS: Our results confirm that women who smoked had an earlier age at natural menopause, while use of oral contraceptives, higher number of pregnancies, and irregularity of menses were associated with a prolonged reproductive lifespan. No associations were observed for dietary habits assessed after the age of 40 years.

Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.

BACKGROUND: Artificial fluoridation of drinking water to improve dental health has long been a topic of controversy. Opponents of this public health measure have cited the possibility of bone cancer induction. The study objective was to examine whether increased risk of primary bone cancer was associated with living in areas with higher concentrations of fluoride in drinking water. METHODS: Case data on osteosarcoma and Ewing sarcoma, diagnosed at ages 0-49 years in Great Britain (GB) (defined here as England, Scotland and Wales) during the period 1980-2005, were obtained from population-based cancer registries. Data on fluoride levels in drinking water in England and Wales were accessed through regional water companies and the Drinking Water Inspectorate. Scottish Water provided data for Scotland. Negative binomial regression was used to examine the relationship between incidence rates and level of fluoride in drinking water at small area level. RESULTS: The study analysed 2566 osteosarcoma and 1650 Ewing sarcoma cases. There was no evidence of an association between osteosarcoma risk and fluoride in drinking water [relative risk (RR) per one part per million increase in the level of fluoride = 1·001; 90% confidence interval (CI) 0·871, 1·151] and similarly there was no association for Ewing sarcoma (RR = 0·929; 90% CI 0·773, 1·115). CONCLUSIONS: The findings from this study provide no evidence that higher levels of fluoride (whether natural or artificial) in drinking water in GB lead to greater risk of either osteosarcoma or Ewing sarcoma.

Increasing incidence of thyroid cancer in Great Britain, 1976-2005: age-period-cohort analysis.

Increases in the incidence of thyroid cancer have been previously reported. The purpose of the present study was to examine temporal trends in the incidence of primary thyroid cancer diagnosed in 0-49 year olds in parts of Great Britain during 1976-2005. Data on 4,337 cases of thyroid cancer were obtained from regional cancer registries. Age-standardized incidence rates (ASRs) were calculated. Negative binomial regression was used to examine effects of age, sex, drift (linear trend), non-linear period and non-linear cohort. The best fitting negative binomial regression model included age (P < 0.001), sex (P < 0.001) and drift (P < 0.001). Non-linear period (P = 0.648) and non-linear cohort (P = 0.788) were not statistically significant. For males aged 0-14, the ASR increased from 0.2 per million persons per year in 1976-1986 to 0.6 in 1997-2005. For males aged 15-29 and 30-49 the ASRs increased from 1.9 to 3.3 and from 7.4 to 12.7, respectively. For females aged 0-14, the corresponding ASR increased from 0.3 to 0.5. For females aged 15-29 and 30-49 the ASRs increased from 6.9 to 12.4 and from 21.2 to 42.3, respectively. For all age groups, there has been a linear increase in incidence of thyroid cancer, which has led to a doubling of the number of cases diagnosed over a twenty year span. The reasons for this increase are not well understood, but it is consistent with findings from other countries.