Reproductive factors and breast cancer risk in Iceland. A second cohort study

In a previous prospective study we showed elevated risks for breast cancer in nulliparous women compared to parous women, in those having their first pregnancy at a higher age, and those with few children. This was based on 216 women diagnosed with breast cancer during 1965 to 1975 among 34,525 women having attended the cervix cancer detection clinic in Iceland by the end of 1974, and born between 1906 and 1945. The present investigation on 848 cases, diagnosed among 6 1,040 women attending the cervix cancer detection clinic during 1964 to 1984 and born between 1901 and 1960, shows the same risk factors to be significant. The relative risks are, however, smaller. The reasons for the difference in relative risks are discussed, We find that the effect of age at first birth is significant for women up to the age of 65 and not for older women. In both cohorts, women older than 55 are underrepresented and more so in the earlier report. In addition, the small number of cases in the reference group with age at first birth below 20 appears to have made the figures of our earlier report unreliable.     

Transgenic mouse models of breast cancer

Summary Although valuable initial information can be gathered about transformation fromin vitro studies, human cancer occurs in the context of a complex interaction with its environment and must ultimately be studied in living animals. Transgenic animal models have been used to study breast transformation for a number of years and have yielded valuable information on the subject. In this paper, we will summarize results from our laboratories, and others, regarding the use of transgenic mice to study breast tumorigenesis. We will also suggest future directions for the use of transgenic models to understand, and hopefully, one day to cure the disease. Note: genes are referred to as lowercase names in italics (e.g.myc) and their protein products as uppercase (e.g. Myc).     

Association between trans fatty acid intake and cardiovascular risk factors in Europe: the TRANSFAIR study

BACKGROUND: High intakes of trans fatty acids (TFA) have been found to exert an undesirable effect on serum lipid profiles, and thus may increase the risk for cardiovascular disease. OBJECTIVES: Investigation of the association between TFA intake and serum lipids. DESIGN: Cross-sectional study in eight European countries (Finland, France, Greece, Iceland, The Netherlands, Portugal, Spain, Sweden) among 327 men and 299 women (50-65 y). Using a dietary history method, food consumption was assessed and TFA intake was calculated with recent figures on TFA levels of foods, collected in the TRANSFAIR study. RESULTS: Mean (+/-s.d.) TFA intake was 2.40+/-1.53 g/day for men and 1.98+/-1.49 g/day for women (0.87+/-0.48% and 0. 95+/-0.55% of energy, respectively), with the highest consumption in Iceland and the lowest in the Mediterranean countries. No associations were found between total TFA intake and LDL, HDL or LDL/HDL ratio after adjustment for cardiovascular risk factors. Additional adjustment for other fatty acid clusters resulted in a significant inverse trend between total TFA intake and total cholesterol (Ptrend<0.03).The most abundantly occurring TFA isomer, C18:1 t, contributed substantially to this inverse association. The TFA isomers C14:1 t9, C16:1 t9 and C22:1 t were not associated or were positively associated with LDL or total cholesterol. CONCLUSIONS: From this study we conclude that at the current European intake levels of trans fatty acids they are not associated with an unfavourable serum lipid profile. SPONSORSHIP: Unilever Research Laboratorium, the Dutch Dairy Foundation on Nutrition and Health, Cargill BV, the Institute of Food Research Norwich Laboratory, the Nutrition Branch of the Ministry of Agriculture, Fisheries and Food, the International Fishmeal and Oil Manufacturers' Association, Kraft Foods, NV Vandemoortele Coordination Center, Danone Group, McDonalds Deutschland Inc, Danish Veterinary and Food Administration, Valio Ltd, Raisio Group. European Journal of Clinical Nutrition (2000) 54, 126-135     

The burden of genital warts: a study of nearly 70,000 women from the general female population in the 4 Nordic countries

OBJECTIVE: To assess the burden and correlates of genital warts in women. METHODS: We conducted a population-based cross-sectional study in 69,147 women (18-45 years of age) randomly chosen from the general population in Denmark, Iceland, Norway, and Sweden. Information on clinically diagnosed genital warts and lifestyle habits was collected using a questionnaire. RESULTS: Overall, 10.6% reported ever having had clinically diagnosed genital warts. In addition, 1.3% reported having experienced genital warts within the past 12 months. The cumulative incidence for different birth cohorts, estimated on the basis of age at first diagnosis of genital warts, increased with each subsequent younger birth cohort (P<.01). The lifetime number of sex partners was strongly correlated with a history of genital warts (odds ratio for > or =15 partners vs. 1 partner, 9.45 [95% confidence interval, 7.89-11.30]). The likelihood of reporting genital warts also increased with a history of sexually transmitted disease, use of hormonal contraceptives, use of condoms, smoking, and higher education. CONCLUSIONS: The data suggest that 1 in 10 women in the Nordic countries experience genital warts before the age of 45 years, with an increasing occurrence in younger birth cohorts. These data are important for developing and evaluating strategies (e.g., human papillomavirus [HPV] vaccination) to control and prevent HPV infection and disease in the population.     

Occupational solvent exposure and adult chronic lymphocytic leukemia: No risk in a population‐based case–control study in four Nordic countries

The aim of this study was to assess the effect of occupational solvent exposure on the risk of adult chronic lymphocytic leukemia (CLL). The current case–control study was nested in the Nordic Occupational Cancer Study (NOCCA) cohort. 20,615 CLL cases diagnosed in 1961–2005 in Finland, Iceland, Norway, and Sweden, and 103,075 population‐based controls matched by year of birth, sex, and country were included. Occupational histories for cases and controls were obtained from census records in 1960, 1970, 1980/1981, and 1990. Exposure to selected solvents was estimated by using the NOCCA job‐exposure matrix (NOCCA‐JEM). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by using conditional logistic regression models. Overall, nonsignificant CLL risk elevations were observed for methylene chloride, perchloroethylene, and 1,1,1‐trichloroethane. Compared to unexposed, significantly increased risks were observed for cumulative perchloroethylene exposure ≤13.3 ppm‐years (OR = 1.85, 95% CI 1.16–2.96) and average life‐time perchloroethylene exposure ≤2.5 ppm (1.61, 95% CI 1.01–2.56) among women, and cumulative methylene chloride exposure ≤12.5 ppm‐years (OR = 1.19, 95% CI 1.01–1.41) and 12.5–74.8 ppm‐years (OR = 1.23, 95% CI 1.01–1.51) among men in an analysis with 5 years lag‐time, though without dose–response pattern. Decreased CLL risk was observed for aliphatic and alicyclic hydrocarbon solvents and toluene. This study did not support associations for solvent exposure and CLL. Observed weak associations for methylene chloride, perchloroethylene, 1,1,1‐trichloroethane exposures, aliphatic and alicyclic hydrocarbons and toluene were not consistent across sexes, and showed no gradient with amount of exposure.     

A history of sexual abuse and health: a Nordic multicentre study

OBJECTIVES: To determine if a history of sexual abuse is associated with objective and subjective indicators of health and if certain abusive incidents had a stronger impact on health than others. DESIGN: A cross-sectional, multicentre study. SETTING: Five gynaecological departments in the five Nordic countries. SAMPLE: Three thousand five hundred and thirty-nine gynaecology patients. METHODS: The NorVold Abuse Questionnaire (NorAQ) on abuse history and current health was mailed to all patients who consented to participate. MAIN OUTCOME MEASURES: Reason for index visit at the gynaeocological clinic as well as several questions on health were recorded. General health status was measured as self-estimated health, psychosomatic symptoms (headache, abdominal pain, muscle, weakness, dizziness), number of health care visits and number of periods on sick leave. RESULT: A history of sexual abuse was reported by 20.7% of respondents. A history of sexual abuse was significantly associated with chronic pelvic pain as reason for index visit (P < 0.01), laparoscopic surgery (P < 0.01), psychosomatic symptoms (P < 0.01), self-estimated poor health (P < 0.01), many health care visits (P < 0.01) and high incidence of sick leave (P < 0.01). Several subgroups within the group of sexually abused women were more likely to report poor health: women abused as both children and adults, women who experienced additional emotional and/or physical abuse and women abused by a person they knew. CONCLUSION: Sexual abuse has a profound impact on women's health. Taking a history of sexual abuse seems particularly warranted when the patient presents with chronic pelvic pain or symptoms of a vague and diffuse nature.     

Diet,pregnancy, and lactation: Effects on adipose tissue,lipoprotein lipase,and fat cell size

Adipose tissue fat cell size and lipoprotein lipase (LPL) activity were determined in the retroperitoneal and subscapular depots of nonpregnant, pregnant, and postpartum rats fed either a standard laboratory diet or a high-fat diet containing 55% fat by wieght. High-fat feeding for 20 days increased, in nonpregnant rats, fat cell size and LPL activity two-to threefold in both depots. In pregnant rats at term, fat cell size was increased and LPL activity was depressed in both dietary groups. Twenty days postpartum, both retroperitoneal fat cell size and LPL activity were decreased in proportion to the size of the litter. Rats not allowed to lactate had fat cell sizes and LPL activity that were not significantly different than in nonpregnant controls. Fat cell size and LPL activity in rats nursing four pups were reduced to 77% and 36% of control, respectively. Those nursing a normal-sized litter of eight pups demonstrated a further reduction of fat cell size to 38% and of LPL activity to 2% of nonpregnant control values. High-fat feeding and obesity did not prevent the fat loss and decreased LPL activity associated with lactation; fat cell size was decreased to 61% and LPL activity to 3% of control values. Values for the subscapular depot followed essentially the same pattern as that observed for the retroperitoneal depot. Mammary LPL activity was increased more than tenfold in animals nursing four or eight pups compared with values at term, whereas no activity was detected in rats not allowed to lactate.     

Trichothiodystrophy, a human DNA repair disorder with heterogeneity in the cellular response to ultraviolet light

Trichothiodystrophy (TTD) is an autosomal recessive disorder characterized by brittle hair with reduced sulfur content, ichthyosis, peculiar face, and mental and physical retardation. Some patients are photosensitive. A previous study by Stefanini et al. (Hum. Genet., 74: 107-112, 1986) showed that cells from four photosensitive patients with TTD had a molecular defect in DNA repair, which was not complemented by cells from xeroderma pigmentosum, complementation group D. In a detailed molecular and cellular study of the effects of UV light on cells cultured from three further TTD patients who did not exhibit photosensitivity we have found an array of different responses. In cells from the first patient, survival, excision repair, and DNA and RNA synthesis following UV irradiation were all normal, whereas in cells from the second patient all these responses were similar to those of excision-defective xeroderma pigmentosum (group D) cells. With the third patient, cell survival measured by colony-forming ability was normal following UV irradiation, even though repair synthesis was only 50% of normal and RNA synthesis was severely reduced. The excision-repair defect in these cells was not complemented by other TTD cell strains. These cellular characteristics of patient 3 have not been described previously for any other cell line. The normal survival may be attributed to the finding that the deficiency in excision-repair is confined to early times after irradiation. Our results pose a number of questions about the relationship between the molecular defect in DNA repair and the clinical symptoms of xeroderma pigmentosum and TTD.