Ditte Vassard

Design of the OPUS School Meal Study: a randomised controlled trial assessing the impact of serving school meals based on the New Nordic Diet.

Introduction: Danish children consume too much sugar and not enough whole grain, fish, fruit, and vegetables. The Nordic region is rich in such foods with a strong health-promoting potential. We lack randomised controlled trials that investigate the developmental and health impact of serving school meals based on Nordic foods. Aim: This paper describes the rationale, design, study population, and potential implications of the Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study. Methods: In a cluster-randomised cross-over design, 1021 children from 3rd and 4th grades (8–11 years old) at nine Danish municipal schools were invited to participate. Classes were assigned to two 3-month periods with free school meals based on the New Nordic Diet (NND) or their usual packed lunch (control). Dietary intake, nutrient status, physical activity, cardiorespiratory fitness, sleep, growth, body composition, early metabolic and cardiovascular risk markers, illness, absence from school, wellbeing, cognitive function, social and cultural features, food acceptance, waste, and cost were assessed. Results: In total, 834 children (82% of those invited) participated. Although their parents were slightly better educated than the background population, children from various socioeconomic backgrounds were included. The proportion of overweight and obese children (14%) resembled that of earlier examinations of Danish school children. Drop out was 8.3%. Conclusions: A high inclusion rate and low drop out rate was achieved. This study will be the first to determine whether school meals based on the NND improve children’s diet, health, growth, cognitive performance, and early disease risk markers.

Medical and social egg freezing: internet-based survey of knowledge and attitudes among women in Denmark and the UK

Until recently, limited options for preserving fertility in order to delay childbearing were available. Although egg freezing and successful thawing is now possible, it remains unclear to what extent women are aware of the availability of this technique, their attitudes towards its use, or the circumstances under which this technique may be considered.

Academic performance in adolescents born after ART—a nationwide registry-based cohort study

STUDY QUESTION Is academic performance in adolescents aged 15–16 years and conceived after ART, measured as test scores in ninth grade, comparable to that for spontaneously conceived (SC) adolescents? SUMMARY ANSWER ART singletons had a significantly lower mean test score in the adjusted analysis when compared with SC singletons, yet the differences were small and probably not of clinical relevance. WHAT IS KNOWN ALREADY Previous studies have shown similar intelligence quotient (IQ) levels in ART and SC children, but only a few have been on adolescents. Academic performance measured with standardized national tests has not previously been explored in a complete national cohort of adolescents conceived after ART. STUDY DESIGN, SIZE, DURATION A Danish national registry-based cohort including all 4766 ART adolescents (n = 2836 singletons and n = 1930 twins) born in 1995–1998 were compared with two SC control cohorts: a randomly selected singleton population (n = 5660) and all twins (n = 7064) born from 1995 to 1998 in Denmark. Nine children who died during the follow-up period were excluded from the study. PARTICIPANTS/MATERIALS, SETTING, METHODS Mean test scores on a 7-point-marking scale from −3 to 12 were compared, and adjustments were made for relevant reproductive and socio-demographic covariates including occupational and educational level of the parents. MAIN RESULTS AND THE ROLE OF CHANCE The crude mean test score was higher in both ART singletons and ART twins compared with SC adolescents. The crude mean differences were +0.41 (95% CI 0.30–0.53) and +0.45 (95% CI 0.28–0.62) between ART and SC singletons and between ART and SC twins, respectively. However, the adjusted mean overall test score was significantly lower for ART singletons compared with SC singletons (adjusted mean difference −0.15 (95% CI −0.29−(−0.02))). For comparison, the adjusted mean difference was +2.05 (95% CI 1.82–2.28) between the highest and the lowest parental educational level, suggesting that the effect of ART is weak compared with the conventional predictors. The adjusted analyses showed significantly lower mean test scores in mathematics and physics/chemistry for ART singletons compared with SC singletons. Comparing ART twins with SC twins yielded no difference in academic performance in the adjusted analyses. Similar crude and adjusted overall mean test scores were found when comparing ART singletons and ART twins. LIMITATIONS, REASONS FOR CAUTION Missing data on educational test scores occurred in 6.6% of adolescents aged 15–16 years for the birth cohorts 1995–1997, where all of the children according to their age should have passed the ninth grade exam at the time of data retrieval. As sensitivity analyses yielded no significant difference in the adjusted risk of having missing test scores between any of the groups, it is unlikely that this should bias our results. Adjustment for body mass index and smoking during pregnancy was not possible. WIDER IMPLICATIONS OF THE FINDINGS As our results are based on national data, our findings can be applied to other populations. The findings of this paper suggest that a possible small negative effect of parental subfertility or ART treatment is counterbalanced by the higher educational level in the ART parents. STUDY FUNDING/COMPETING INTEREST(S) The Danish Medical Association in Copenhagen (KMS) funded this study with a scholarship grant. None of the authors had any competing interests. TRIAL REGISTRATION NO. (STATISTICS DENMARK) 704676.

A population-based survey on family intentions and fertility awareness in women and men in the United Kingdom and Denmark

Abstract Background: Across several European countries family formation is increasingly postponed. The aims of the study were to investigate the desire for family building and fertility awareness in the UK and Denmark. Methods: A population-based internet survey was used among women (n = 1,000) and men (n = 237) from the UK (40%) and Denmark (60%). Data covered socio-demographics, family formation, and awareness of female age-related fertility. Data analysis used descriptive statistics and logistic regression analysis for studying associations between low fertility awareness and desired family formation. Results: The majority of all participants desired two or three children. Two-thirds of the childless participants desired a first child at 30+ years, and one-fifth of the women and one-third of the men desired a last child at age 40. Overall, 83% of women and 73% of men were aware that female fertility starts to decline around 25–30 years. Men had significantly lower fertility awareness. Women who underestimated the impact of age on female fertility were significantly more likely to have a desire or attempted their first child at a higher age. Conclusion: Even though the majority were aware of the age-related decrease in female fertility, most desired having children at an age when female fertility has declined. Women who were not sufficiently aware of the impact of advanced age were significantly more likely to have their first child at a higher age. There is a need for developing educational programs for women and men in order to increase the population’s knowledge of fertility and risk factors for infertility.

Male Infertility and Risk of Nonmalignant Chronic Diseases: A Systematic Review of the Epidemiological Evidence

Abstract The association between male infertility and increased risk of certain cancers is well studied. Less is known about the long‐term risk of nonmalignant diseases in men with decreased fertility. A systemic literature review was performed on the epidemiologic evidence of male infertility as a precursor for increased risk of diabetes, cardiovascular diseases, and all‐cause mortality. PubMed and Embase were searched from January 1, 1980, to September 1, 2016, to identify epidemiological studies reporting associations between male infertility and the outcomes of interest. Animal studies, case reports, reviews, studies not providing an accurate reference group, and studies including infertility due to vasectomy or malignancy were excluded. The literature search resulted in 2,485 references among which we identified seven articles fulfilling the eligibility criteria. Of these, four articles were prospective (three on risk of mortality, one on risk of chronic diseases) and three were cross‐sectional relating male infertility to the Charlson Comorbidity Index. The current epidemiological evidence is compatible with an association between male infertility and risk of chronic disease and mortality, but the small number of prospective studies and insufficient adjustment of confounders preclude strong statements about male infertility as precursor of these outcomes.

Risk of diabetes according to male factor infertility: a register-based cohort study.

Abstract STUDY QUESTION Is male factor infertility associated with an increased risk of developing diabetes? SUMMARY ANSWER The study provides evidence that male factor infertility may predict later occurrence of diabetes mellitus with the risk being related to the severity of the underlying fertility problem. WHAT IS KNOWN ALREADY Previous cross-sectional studies have shown an increased prevalence of comorbidities among infertile men when compared to controls. STUDY DESIGN, SIZE, DURATION In this prospective cohort study, 39 516 men who had since 1994 undergone fertility treatment with their female partner were identified from the Danish national IVF register, which includes data on assumed cause of couple infertility (male/female factor, mixed and unexplained infertility) and type of fertility treatment. With a median follow-up time of 5.6 years, each man was followed for diabetes occurrence from enrollment until 31 December 2012 using the National Diabetes Register (NDR). Men with a history of diabetes prior to their fertility diagnosis were excluded. Hazard ratios (HR) were estimated by Cox proportional hazard models with age as the underlying time scale. In addition to analyzing the data for the entire IVF registration period (1994–2012), separate analyses were performed for men identified from the first (1994–2005) and second (2006–2012) IVF registration period owing to heterogeneity in the reporting of male factor infertility in these two time periods, because the reason for male factor infertility was not available from the first register. PARTICIPANTS/MATERIALS, SETTING, METHODS Male factor infertility was identified from the variable ‘yes’ or ‘no’ from the first IVF register and through a diagnosis code (e.g. oligospermia, azoospermia) from the second IVF register. The reference group was men with male factor infertility (=‘no’) and those with normal semen quality or sterilized men. Of the included men, 18 499 (46.8%) had male factor infertility and 21 017 (53.2%) made up the reference group. MAIN RESULTS AND THE ROLE OF CHANCE A total of 651 (1.6%) diabetes cases were identified during the follow-up period. The adjusted HRs for diabetes risk among men with male factor infertility when compared to the reference group were HR = 1.08 (95% CI: 0.89, 1.31) and HR = 1.45 (95% CI: 1.06, 1.97) for the first and second IVF registration period, respectively. When assessing the effects of individual causes of male factor infertility, the adjusted HRs for men with oligospermia, azoospermia and aspermia were HR = 1.44 (95% CI: 1.01, 2.06), HR = 2.10 (95% 1.25, 3.56) and HR = 3.20 (95% CI 1.00, 10.31), respectively. LIMITATIONS, REASONS FOR CAUTION We found no increased risk among men identified from the first IVF register, which may be related to exposure misclassification as the reason for male factor infertility was not available from this time period. The NDR does not distinguish between type 1 and type 2 diabetes. WIDER IMPLICATIONS OF THE FINDINGS These findings support previous studies that a mans reproductive and somatic health are closely intertwined and highlight the importance for further monitoring of these men. Further, implementation of diabetes screening may be especially relevant among aspermic and azoospermic men. STUDY FUNDING/COMPETING INTERESTS This article is part of the ReproUnion collaborative study, co-financed by the European Union, Intereg V Öresund-Kattegat-Skagerrak. None of the authors declare any conflict of interest. TRIAL REGISTRATION NUMBER None.

Male factor infertility and risk of multiple sclerosis: A register-based cohort study

Background: Gender, possibly due to the influence of gonadal hormones, is presumed to play a role in the pathogenesis of multiple sclerosis (MS), but no studies have evaluated whether male infertility is associated with MS. Objective: To study the association between male factor infertility and prevalent as well as incident MS. Method: Our cohort was established by linkage of the Danish National in vitro fertilization (IVF) registry to The Danish Multiple Sclerosis Registry and consisted of 51,063 men whose partners had undergone fertility treatment in all public and private fertility clinics in Denmark between 1994 and 2015. Results: With a median age of 34 years at baseline, 24,011 men were diagnosed with male factor infertility and 27,052 did not have male factor infertility and made up the reference group. Men diagnosed with male factor infertility had a higher risk of prevalent (odds ratio (OR) = 1.61, 95% confidence interval (95% CI) 1.04–2.51) and incident MS (hazard ratio (HR) = 1.28, 95% CI 0.76–2.17) when compared to the reference group. Conclusion: This nationwide cohort study has shown, for the first time, an association between male infertility and MS which may be due to underlying common etiologies such as hypogonadism, shared genetics, or a joint autoimmune component.

Parental socioeconomic position and risk of ADHD in offspring: a cohort study of 9648 individuals in Denmark 1976–2013

The strength of the association between parental socioeconomic position (SEP) and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring is found to vary substantially, perhaps due to the negligence of possible changes in parental life course SEP. The present study investigated the association between parental SEP in adulthood and risk of ADHD diagnosis in offspring and whether parental childhood SEP modified this association. The study population included 9648 live-born singletons followed in the Psychiatric Central Register from birth in 1976–1996 until 2013. Cox regression was used to estimate hazard ratios for ADHD diagnosis according to parental SEP in adulthood. The results showed that low parental SEP in adulthood was associated with higher risk of ADHD diagnosis in offspring, also after adjustment for possible confounders. Thus, offspring of parents with low SEP in adulthood had 4.52 (95% CI 2.81–7.26) times higher hazard of ADHD diagnosis compared with offspring of parents with high SEP in adulthood. Further, parental childhood SEP was found to modify the observed association. Thus, offspring of parents with downward social mobility from childhood to adulthood and offspring of parents with stable low SEP experienced the highest risk of ADHD diagnosis, followed by offspring of parents with upward social mobility, compared with offspring of parents with stable high SEP. The results suggest that it is important to take into account the possibility of social mobility as changes in parental life course SEP from childhood to adulthood seem to influence the risk of ADHD diagnosis in offspring.

Mortality in Women Treated With Assisted Reproductive Technology—Addressing the Healthy Patient Effect

In previous studies, investigators have reported reduced mortality among women undergoing assisted reproductive technology (ART) treatment, possibly related to selection of healthy women into ART treatment. Our aim in this study was to explore the impact of relevant selection factors on the association between ART treatment and mortality and to explore effect modification by parity. Women treated with ART in fertility clinics in Denmark during 1994-2009 (n = 42,897) were age-matched with untreated women from the background population (n = 204,514) and followed until December 31, 2010. With adjustment for relevant confounders, the risk of death was lower among ART-treated women during the first 2 years after ART treatment (hazard ratio (HR) = 0.68, 95% confidence interval (CI): 0.63, 0.74), but there was no apparent difference after 10 years (HR = 0.92, 95% CI: 0.79, 1.07). Having children prior to ART treatment was associated with markedly reduced mortality (HR = 0.45, 95% CI: 0.38, 0.53), possibly due to better health among fertile women. While the frequencies of previous medical and psychiatric diagnoses among ART-treated and untreated women were similar, differences in disease severity could explain the reduced mortality among ART-treated women, as poor prognosis would make initiation of ART treatment unlikely. The survival advantage among ART-treated women is likely a selection phenomenon rather than a biological phenomenon.

Use and Preference of Advice on Small Children's Food: Differences Between Parents From Ethnic Minority, Ethnic Majority, and Mixed Households

The authors analyzed the influence of acculturation on parental attitudes to, and use of, different sources of health advice about young childrens food in Denmark. Using combined ethnic position of the childrens parents as a proxy for household acculturation, the authors conducted a postal survey of 2,511 households with young children (6 months to 3.5 years) occupying ethnic minority, ethnic majority, or ethnic mixed position. The analysis showed that the use of advice differed in the 3 groups. Households with ethnic minority status were more likely to use the childs grandparents, general practitioners, and hospital staff as information sources, while households with ethnic majority status were more likely to use mothers’ peer groups and written material. In all types of household municipal public health nurses were relied on as a source of advice on young childrens food, but households with ethnic minority status were more likely to find the advice obtained in this way incompatible with their family eating habits. Although existing dietary health communication strategies delivered by public health nurses appear to work well in all household types, parents from minority households seem to experience dilemmas. These may be related to their cultural and generational status at the time of receiving the advice. Adjustments to current communication strategies on young childrens food are suggested.