Use of fertility drugs in Denmark 1973-1993. An analysis based on sale statistics

Impaired fecundity as a marker of health and survival: a Danish twin cohort study

STUDY QUESTION

Is fecundity, measured as self-reported time to first pregnancy (TTP), a marker for subsequent health and survival?

SUMMARY ANSWER

Long TTP was a marker for increased mortality among women and higher hospitalization rates for both women and men.

WHAT IS KNOWN ALREADY

Poor semen quality has been linked to increased mortality and morbidity from a wide range of diseases. Associations among fecundity, health and survival among women are still uncertain and studies on actual measures of fecundity and health outcomes are rare.

STUDY DESIGN, SIZE, DURATION

We performed a prospective cohort study of 7825 women and 6279 men, aged 18 and above with measures on first TTP, who participated in one of the Danish nation-wide twin surveys in 1994 (twins born 1953-1976) and 1998 (twins born 1931-1952). They were followed-up for mortality and hospital admissions from the interview until 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Twins were identified in the Danish Twin Registry and linked to Danish registers. TTP was restricted to the first pregnancy as a categorical outcome with cut-off points at 2, 10 and 18 months. We analysed the association between TTP and survival using a Cox proportional hazards model estimating hazards ratios (HRs) with 95% confidence intervals (CIs). Fine-Gray survival models were used to estimate sub-hazard ratios for specific causes of death allowing for competing risks. Using negative binomial regression, we estimated incidence rate ratios (IRRs) with 95% CIs for all-cause and cause-specific hospitalizations. All analyses were stratified by sex and adjusted for age at interview, birth cohorts, age at first attempt to become pregnant, smoking, years in school and BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

In the total study population, 49.9% of women and 52.7% of men reported a TTP of less than 2 months, 30.8% of women and 29.6% of men reported a TTP of 2-9 months, 6.6% of women and 5.7% of men reported a TTP of 10-17 months, and 13.3% of women and 12.0% of men reported a TTP of 18 months or more. Among 1305 deaths, we found a higher mortality for women (HR = 1.46; 95% CI 1.15, 1.87) with a TTP of ≥18 months relative to those with a TTP of <2 months, while the highest mortality was indicated for men with a TTP of 10-17 months (HR = 1.31; 95% CI 0.98, 1.74). Among 53 799 hospitalizations, we found an increased hospitalization rate among women (HR = 1.21; 95% CI 1.0-1.41) and men (HR = 1.16; 95% CI 1.00-1.35) with a TTP of ≥18 months, and for men with a TTP of 2-9 months (HR = 1.14; 95% CI 1.01-1.30). A dose-response relationship was found for women regarding both mortality (P = 0.022) and hospitalizations (P = 0.018). Impaired fecundity was associated with a wide range of diseases and some causes of death, indicating a multi-factorial causal influence on fecundity, especially among women.

LIMITATIONS, REASONS FOR CAUTION

A major limitation was that fecundity depends on both partners, which was not considered in this study. Moreover, we could not obtain information on a number of potential confounders.

WIDER IMPLICATIONS OF THE FINDINGS

Fecundity seems positively correlated with overall health and may be a universal marker of future health and survival. These results add knowledge to the limited findings showing that reduced fecundity in women and poor semen quality in men may reflect worse health and a shorter life, particularly among women.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by NIH grant HD096468 (M.L.E., T.K.J. and R.L.J.). The authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

[Medical service use for infertility in French private sector]

OBJECTIVES

This study presents nationally representative estimates and trends for infertility service use among women aged 25-43 and men aged 25-49 in France in 2013-2016.

METHODS

Two retrospective repeated cross-sectional analyses for years 2013 to 2016 were performed on the statutory French health care insurance reimbursement database for independent workers. Use rate was calculated on the number of individuals who underwent at least one infertility service within the studied year per women and men who utilized health services the same year.

RESULTS

1.69% [IC 95%: 1.65; 1.72] of women aged 25-43 who utilized health services had used infertility services during the year 2016: 1.5% used ovulation induction, 0.7% ultrasound monitoring of follicles, 0.3% embryo transfer, 0.3% in vitro fertilization.The use increased significantly from 2013 to 2016 for the following services: ultrasound monitoring of follicles (+ 10%), intracytoplasmic sperm injection (+ 12%), freezing of embryos (+ 32%), thawing of embryos (+ 29%), embryo cryopreservation (+ 88%).In a multivariate analysis, the use was higher among women aged 30-39 years, with a liberal profession, living in the North-east or the south-east, in Corsica or over-seas, receiving health care outside the French territory.0.19% [IC 95%: 0.18; 0.20] of men aged 25-49 years had used infertility services during the year.There was a significant increase from 2013 to 2016 of the proportion of users for sperm freezing (+ 19.18%) and sperm cryopreservation for fertility preservation when cytotoxic therapy is required (+ 84.92%).

CONCLUSION

Some increases resulted from expanded indications. Follow-up will be required in case of legislative enlargement for access to certain techniques.

Maternal use of fertility drugs and risk of cancer in children--a nationwide population-based cohort study in Denmark

Large population-based studies are needed to examine the effect of maternal use of fertility drugs on the risk of cancer in children, while taking into account the effect of the underlying infertility. A cohort of 123,322 children born in Denmark between 1964 and 2006 to 68,255 women who had been evaluated for infertility was established. We used a case-cohort design and calculated hazard ratios (HRs) for cancer in childhood (0-19 years) and in young adulthood (20-29 years) associated with maternal use of six groups of fertility drugs (clomiphene, gonadotropins [i.e., human menopausal gonadotropins and follicle-stimulating hormone], gonadotropin-releasing hormone analogs, human chorionic gonadotropins, progesterone and other fertility drugs). We found no statistically significant association between maternal use of fertility drugs and risk for overall cancer in childhood or young adulthood. However, with regard to specific cancers in childhood, our results showed that maternal use of progesterone before childbirth markedly increased the risks of their offspring for acute lymphocytic leukemia (any use: HR, 4.95; 95% CI, 1.69-14.54; ≥ three cycles of use: HR, 9.96; 95% CI, 2.63-37.77) and for sympathetic nervous system tumors (any use: HR, 5.79; 95% CI, 1.23-27.24; ≥ three cycles of use: HR, 8.51; 95% CI, 1.72-42.19). These findings show that maternal use of progesterone may increase the risk for specific cancers in the offspring. Additional large epidemiological studies are urgently needed to confirm our finding.

Risk of breast cancer and gynecologic cancers in a large population of nearly 50,000 infertile Danish women

Infertility is considered to influence the risk of breast cancer and gynecologic cancers. To assess this association, the authors used data from a large cohort of 54,362 women with a diagnosis of infertility who were referred to Danish fertility clinics between 1963 and 1998. Through 2003, 1,975 cancers were identified by linkage to the Danish Cancer Registry. Cancer risk was assessed through standardized incidence ratios (SIRs) and corresponding 95% confidence intervals, using general and parity-specific cancer incidence rates in the general population of Denmark as a reference. After adjustment for parity status, significantly increased SIRs were observed for breast (SIR = 1.08, 95% confidence interval: 1.01, 1.16) and ovarian (SIR = 1.46, 95% confidence interval: 1.24, 1.71) cancer. The risk of breast cancer increased with follow-up time. Similar risk patterns were observed for the different histologic types of breast cancer and all nonmucinous types of ovarian cancer, whereas the risk of mucinous ovarian cancers seemed not to be increased. These data thus suggest higher risks of breast and ovarian cancer among infertile women. However, since these results could not distinguish the effects of underlying infertility from the effects of fertility treatment, additional studies are needed to disentangle the effects of these two factors.

Malignant melanoma risk after exposure to fertility drugs: results from a large Danish cohort study

OBJECTIVE

The aim was to examine the effects of fertility drugs on malignant melanoma risk using data from the largest cohort of infertile women to date.

METHODS

A cohort of 54,362 women with infertility problems referred to Danish fertility clinics in the period 1963-1998 was established. A detailed data collection including information about type and amount of treatment was conducted. Using case-cohort techniques, we calculated rate ratios (RRs) of malignant melanoma associated with different fertility drugs after adjustment for parity status.

RESULTS

112 malignant melanomas were identified during follow-up through 2000. Use of clomiphene, gonadotrophins, hCG or GnRH did not affect risk of malignant melanoma significantly. When stratifying for parity, however, use of gonadotrophins (RR = 2.29; CI: 1.16-4.52) or GnRH (RR = 3.26; 95% CI: 1.50-7.09) among parous women was associated with a significant increased risk. For all groups of fertility drugs, we found no association with number of cycles of use or years since first use (latency).

CONCLUSIONS

Our findings showed no strong association between malignant melanoma risk and use of fertility drugs, although the results indicated that use of gonadotrophins or GnRH might increase risk in parous women. Longer follow-up is needed to confirm our findings.

Risk of Breast Cancer After Exposure to Fertility Drugs: Results from a Large Danish Cohort Study

BACKGROUND

Few epidemiologic studies have examined the association between fertility drugs and breast cancer risk, and results have been contradicting. Using data from the largest cohort of infertile women to date, the aim of this study was to examine the effects of fertility drugs on breast cancer risk overall and according to histologic subtypes.

METHOD

A cohort of 54,362 women with infertility problems referred to all Danish fertility clinics between 1963 and 1998 was established. A detailed data collection, including information of type and amount of treatment, was conducted. We used case-cohort techniques to calculate rate ratios (RR) of breast cancer associated with use of five groups of fertility drugs, after adjustment for parity status.

RESULTS

Three hundred thirty-one invasive breast cancers were identified in the cohort during follow-up through 1998. Analyses within cohort showed no overall increased breast cancer risk after use of gonadotrophins, clomiphene, human chorionic gonadotrophin, or gonadotrophin-releasing hormone, whereas use of progesterone increased breast cancer risk (RR, 3.36; 95% confidence interval, 1.3-8.6). For all groups of fertility drugs, no relationships with number of cycles of use or years since first use of fertility drug were found. However, gonadotrophins may have a stronger effect on breast cancer risk among nulliparous women (RR, 1.69; 95% confidence interval, 1.03-2.77). Similar risk patterns were present for ductal, lobular, and tumors of other histologies, indicating identical etiologies.

CONCLUSION

The results showed no strong association between breast cancer risk and use of fertility drugs. Follow-up is, however, needed to assess long-term breast cancer risk after use of progesterone and among nulliparous women exposed to gonadotrophins.

Trends in the incidence and mortality of ovarian cancer in Denmark 1978-2002. Comparison with other Nordic countries

BACKGROUND

The Nordic countries are well-known high-incidence areas of ovarian cancer, but even within the Nordic countries, differences exist.

METHODS

Focus in this descriptive epidemiological study is to assess developments in incidence and mortality of ovarian cancer in Denmark 1978-2002 and to make a comparison with the development in the other Nordic countries. The results are based on data from the nationwide Danish Cancer Registry as well as the other Nordic Cancer Registries.

RESULTS

A total of 14,325 cases of ovarian cancer were registered from 1978 to 2002 in Denmark. In this period, the age-standardized incidence decreased slightly from 14.3 (1978-1982) to 13.3 per 100,000 woman-years (1998-2002). The histology-specific time trends showed a tendency towards more specified histological diagnoses. Iceland had the highest age-adjusted ovarian cancer incidence in the Nordic countries, whereas Denmark had the highest mortality rate. In the entire period, the Danish mortality rate declined from 10.8 (1978-1982) to 9.0 per 100,000 woman-years (1998-1999). Only 19% of ovarian cancers in Denmark from 1978 to 2002 were localized at the time of diagnosis, while 30% had distant metastases. Older women were more likely to have advanced disease at diagnosis. The Danish distribution of stage at diagnosis seems less favorable compared to results from other countries.

CONCLUSIONS

The Danish incidence of ovarian cancer seemed to decrease slightly from 1978 to 2002. Even though the mortality rate of ovarian cancer also declined, Denmark had the highest mortality rate of ovarian cancer in the world. Part of it may be explained by a less-favorable distribution of stage at diagnosis.

Ovarian stimulation and borderline ovarian tumors: a case-control study

OBJECTIVE

To assess the risk of borderline ovarian cancer among infertile women treated with fertility drugs.

DESIGN

Case-control study.

SETTING

Nationwide data obtained from public registers and postal questionnaires.

PATIENT(S)

All Danish women <60 years old with borderline ovarian cancer during the period 1989-1994 and randomly selected population controls. The analysis included 231 cases and 1,721 controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Influence of parity, infertility, and fertility drugs on the risk of borderline ovarian cancer after multivariate confounder control.

RESULT(S)

The odds ratio (OR) for borderline ovarian cancer among infertile untreated nulliparous women compared with fertile nulliparous women was 1.9. The OR for borderline ovarian cancer among treated nulliparous women compared with untreated infertile nulliparous women was 1.5, and the OR among treated parous women compared with untreated infertile parous women was 1.5.

CONCLUSION(S)

Among fertile women, the difference in the risk of borderline ovarian cancer between nulliparous women and parous women was not statistically significant. Nulliparous women who were infertile and who did not receive medical treatment had a twofold higher risk of borderline ovarian cancer than fertile nulliparous women. There was no statistically significant increase in the risk of borderline ovarian cancer among nulliparous women who were treated with fertility drugs compared with nulliparous untreated infertile women or among parous women who were treated with fertility drugs compared with parous untreated infertile women.

Infertility, fertility drugs, and invasive ovarian cancer: a case-control study

OBJECTIVE

To assess the risk of invasive ovarian cancer among infertile women treated with fertility drugs.

DESIGN

A case-control study.

SETTING

Nationwide data based on public registers.

PATIENT(S)

All Danish women (below the age of 60 years) with ovarian cancer during the period from 1989 to 1994 and twice the number of age-matched population controls. Included in the analysis were 684 cases and 1,721 controls.

MAIN OUTCOME MEASURE(S)

Influence of parity, infertility, and fertility drugs on the risk of ovarian cancer after multivariate confounder control. Risk measure(s): odds ratios (OR) with 95% confidence intervals.

RESULT(S)

Nulliparous women had an increased risk of ovarian cancer compared with parous women: OR 1.5 to 2.0. Infertile, nontreated nulliparous women had an OR of 2.7 (1.3 to 5.5) compared with noninfertile nulliparous women. The OR of ovarian cancer among treated nulliparous women was 0.8 (0.4 to 2.0) and among treated parous 0.6 (0.2 to 1.3), compared with nontreated nulliparous and parous infertile women, respectively.

CONCLUSION(S)

Nulliparity implies a 1.5- to 2-fold increased risk of ovarian cancer. Infertility without medical treatment among these women increased the risk further. Among parous as well as nulliparous women, treatment with fertility drugs did not increase the ovarian cancer risk compared with nontreated infertile women.