Comparable Dietary Patterns Describe Dietary Behavior across Ethnic Groups in the Netherlands, but Different Elements in the Diet Are Associated with Glycated Hemoglobin and Fasting Glucose Concentrations.

BACKGROUND: Ethnic minority populations in Western societies suffer from a disproportionate burden of type 2 diabetes (T2D). Insight into the role of dietary patterns in T2D may assist public health nutrition efforts in addressing these health disparities. OBJECTIVE: We explored the association between dietary patterns and biomarkers of T2D in 5 ethnic groups living in Amsterdam, Netherlands. METHODS: A total of 3776 men and women aged 18-70 y of Dutch, South Asian Surinamese, African-Surinamese, Turkish, and Moroccan origin from the HELIUS (HEalthy LIfe in an Urban Setting) study were included. Diet was assessed by using a food-frequency questionnaire, and dietary patterns were derived separately per ethnic group. First, food group-based dietary patterns were derived by using principal components analysis and the association with glycated hemoglobin (HbA1c) and plasma fasting glucose was assessed by using multivariable linear regression. Second, biomarker-driven dietary patterns based on HbA1c and fasting glucose concentrations were derived by applying reduced rank regression. RESULTS: Two comparable food group-based dietary patterns were identified in each ethnic group: a "meat and snack" pattern and a "vegetable" pattern. The meat-and-snack pattern derived within the Dutch origin population was significantly associated with HbA1c (ß = 0.09; 95% CI: 0.00, 0.19) and fasting glucose (ß = 0.18; 95% CI: 0.09, 0.26) concentrations. A biomarker-derived pattern characterized by red and processed meat was observed among Dutch-origin participants; however, among ethnic minority groups, this pattern was characterized by other foods including ethnicity-specific foods (e.g., roti, couscous). CONCLUSIONS: Although similar food group dietary patterns were derived within 5 ethnic groups, the association of the meat-and-snack pattern with fasting glucose concentrations differed by ethnicity. Taken together with the finding of ethnic differences in biomarker-driven dietary patterns, our results imply that addressing T2D risk in multiethnic populations requires ethnicity-specific approaches.

Socio-economic status and ethnicity are independently associated with dietary patterns: the HELIUS-Dietary Patterns study.

BACKGROUND: Differences in dietary patterns between ethnic groups have often been observed. These differences may partially be a reflection of differences in socio-economic status (SES) or may be the result of differences in the direction and strength of the association between SES and diet. OBJECTIVE: We aimed to examine ethnic differences in dietary patterns and the role of socio-economic indicators on dietary patterns within a multi-ethnic population. DESIGN: Cross-sectional multi-ethnic population-based study. SETTING: Amsterdam, the Netherlands. SUBJECTS: Principal component analysis was used to identify dietary patterns among Dutch (n=1,254), South Asian Surinamese (n=425), and African Surinamese (n=784) participants. Levels of education and occupation were used to indicate SES. Linear regression analysis was used to examine the association between ethnicity and dietary pattern scores first and then between socio-economic indicators and dietary patterns within and between ethnic groups. RESULTS: 'Noodle/rice dishes and white meat', 'red meat, snacks, and sweets' and 'vegetables, fruit and nuts' patterns were identified. Compared to the Dutch origin participants, Surinamese more closely adhered to the 'noodle/rice dishes and white meat' pattern which was characterized by foods consumed in a 'traditional Surinamese diet'. Closer adherence to the other two patterns was observed among Dutch compared to Surinamese origin participants. Ethnic differences in dietary patterns persisted within strata of education and occupation. Surinamese showed greater adherence to a 'traditional' pattern independent of SES. Among Dutch participants, a clear socio-economic gradient in all dietary patterns was observed. Such a gradient was only present among Surinamese dietary oatterns to the 'vegetables, fruit and nuts' pattern. CONCLUSIONS: We found a selective change in the adherence to dietary patterns among Surinamese origin participants, presumably a move towards more vegetables and fruits with higher SES but continued fidelity to the traditional diet.

A prospective cohort study of dietary patterns of non-western migrants in the Netherlands in relation to risk factors for cardiovascular diseases: HELIUS-Dietary Patterns.

BACKGROUND: In Western countries the prevalence of cardiovascular disease (CVD) is often higher in non-Western migrants as compared to the host population. Diet is an important modifiable determinant of CVD. Increasingly, dietary patterns rather than single nutrients are the focus of research in an attempt to account for the complexity of nutrient interactions in foods. Research on dietary patterns in non-Western migrants is limited and may be hampered by a lack of validated instruments that can be used to assess the habitual diet of non-western migrants in large scale epidemiological studies. The ultimate aims of this study are to (1) understand whether differences in dietary patterns explain differences in CVD risk between ethnic groups, by developing and validating ethnic-specific Food Frequency Questionnaires (FFQs), and (2) to investigate the determinants of these dietary patterns. This paper outlines the design and methods used in the HELIUS-Dietary Patterns study and describes a systematic approach to overcome difficulties in the assessment and analysis of dietary intake data in ethnically diverse populations. METHODS/DESIGN: The HELIUS-Dietary Patterns study is embedded in the HELIUS study, a Dutch multi-ethnic cohort study. After developing ethnic-specific FFQs, we will gather data on the habitual intake of 5000 participants (18-70 years old) of ethnic Dutch, Surinamese of African and of South Asian origin, Turkish or Moroccan origin. Dietary patterns will be derived using factor analysis, but we will also evaluate diet quality using hypothesis-driven approaches. The relation between dietary patterns and CVD risk factors will be analysed using multiple linear regression analysis. Potential underlying determinants of dietary patterns like migration history, acculturation, socio-economic factors and lifestyle, will be considered. DISCUSSION: This study will allow us to investigate the contribution of the dietary patterns on CVD risk factors in a multi-ethnic population. Inclusion of five ethnic groups residing in one setting makes this study highly innovative as confounding by local environment characteristics is limited. Heterogeneity in the study population will provide variance in dietary patterns which is a great advantage when studying the link between diet and disease.

Are cause of subfertility and in vitro fertilization treatment risk factors for an earlier start of menopause?

OBJECTIVE: To study whether women diagnosed with unexplained subfertility reach the menopause transition and natural menopause earlier than women with tubal subfertility, in an in vitro fertilization (IVF)-treated population, and to examine the influence of the number of IVF cycles on the occurrence of an early menopause transition and natural menopause. DESIGN: This retrospective cohort study included 12 IVF clinics in the Netherlands. A nationwide retrospective cohort study was conducted among women whose first IVF cycle was stimulated with gonadotrophins in the Netherlands between 1983 and 1995 (n = 7,842). Most of the women were in their late 30s at the end of the follow-up period (range 24-55 y). The main outcome measures were the relative risk (RR) of having reached natural menopause and the risks (RR) of having entered the menopause transition or natural menopause according to the cause of subfertility and the number of IVF cycles. RESULTS: Women with unexplained subfertility did not have an increased risk of entering the menopause transition or natural menopause (adjusted RR = 0.5; 95% CI, 0.2-1.5; and RR = 0.8; 95% CI, 0.6-1.1). After a 5-year follow-up period, we found no increased risk for entering the menopause transition or natural menopause among women who had undergone six or more IVF cycles when compared with women who had undergone only one IVF cycle (adjusted RR = 0.4; 95% CI, 0.1-1.7; and RR = 0.9; 95% CI, 0.6-1.6). CONCLUSIONS: Underlying causes of unexplained subfertility do not predispose women to an early start of menopause. Although the number of IVF cycles was not associated with early menopause, longer follow-up is needed.

Validity of self-reported causes of subfertility.

The authors assessed the accuracy of cause(s) of subfertility as reported by women in a self-administered questionnaire in comparison with medical record information, in a nationwide cohort study of women receiving in vitro fertilization treatment in the Netherlands (n = 9,164) between 1983 and 1995. Validity was expressed as sensitivity and specificity, and reliability was expressed by the kappa statistic and overall agreement between self-reports and medical records for various subfertility categories. The sensitivity for subfertility attributed to tubal, male, hormonal, cervical, uterine, and idiopathic factors and for endometriosis was 84%, 78%, 65%, 40%, 46%, 59%, and 83%, respectively. The corresponding kappas were 0.79, 0.71, 0.38, 0.34, 0.13, 0.50, and 0.52, respectively. For 54% of all women who reported two or more causes of subfertility, the medical record revealed only one major factor. Conversely, for 43% of all women whose subfertility was attributed to two or more major factors in the record, only one factor was reported by the women. Older age at the time of filling out the questionnaire, low educational level, long duration of subfertility, and pre-in vitro fertilization treatment were associated with less accurate reporting. The results indicate that the validity of self-reports for tubal and male subfertility is satisfactory. For unexplained subfertility, the validity is moderate; for other causes of subfertility and when two causes of subfertility play a role, the validity is low.

The number of retrieved oocytes does not decrease during consecutive gonadotrophin-stimulated IVF cycles.

BACKGROUND: Our aim was to study whether there is a decreasing trend in the number of retrieved oocytes in women who had all undergone at least seven consecutive IVF cycles. METHODS: A nationwide retrospective cohort study was conducted among women whose first IVF cycle was stimulated with gonadotrophins in The Netherlands between 1983 and 1995. Among these eligible women, we identified all women who had received at least seven consecutive IVF cycles (n = 330). Poisson regression analysis was used to assess the trend in the number of retrieved oocytes over the first six IVF cycles. RESULTS: The unadjusted results showed a slight but non-significant decrease in the number of retrieved oocytes over six IVF cycles. The change in cycle 6 compared with cycle 1 was -0.06 oocytes (5.8% decrease) (P = 0.21). When adjusting for the number of ampoules and the stimulation protocol (fertility drug used combined with use of GnRH agonists), there was a considerable and highly significant decrease from cycle 1 to cycle 6 [change in cycle 6 compared with cycle 1: -0.19 oocytes (17.4% decrease), (P < 0.0001)]. However, when adjusting for age of the women, this decrease almost completely disappeared [change in cycle 6 compared with cycle 1: -0.05 oocytes (5% decrease), (P = 0.50)]. CONCLUSION: The results suggest that there is no decrease in the number of retrieved oocytes over subsequent cycles when simultaneously accounting for the increasing age of the women, differences in the number of ampoules of gonadotrophins used, type of stimulation protocol and year of IVF treatment.

Increased risk of early menopausal transition and natural menopause after poor response at first IVF treatment.

BACKGROUND: Our aim was to examine whether women who had a low number of retrieved oocytes at their first IVF attempt reach the menopausal transition and/or the natural menopause earlier than women of similar ages with a high number of retrieved oocytes. METHODS: We conducted a retrospective cohort study among women in The Netherlands who received IVF treatment between 1983 and 1995. For the present study, we selected all cohort members who had a regular menstrual cycle at the time of the first visit to the gynaecologist (n = 4601). After a median follow-up of 5.5 years, 3871 (84%) women still had a regular menstrual cycle pattern, 547 (12%) women had entered the menopausal transition (i.e. no menses for 3-11 months, use of HRT or irregular menstrual cycles) and 27 (1%) women had reached natural menopause. We examined whether the quantity and the quality of the retrieved oocytes were related to an early menopausal transition and early menopause. The live birth rate per embryo transfer was used as indicative of the quality of the oocytes. RESULTS: The age-adjusted odds ratio (OR) for having entered the menopausal transition/natural menopause for women with a poor response (0-3 oocytes) at their first IVF attempt was 3.1 [95% confidence interval (CI) 2.4-3.8] compared with women with a normal response (>3 oocytes). Women who were stimulated with gonadotrophins during IVF treatment but did not undergo an IVF puncture because of an anticipated poor response (cancelled IVF cycle) had an age-adjusted OR of 3.2 (95% CI 2.3-4.3). There was no significant difference in the odds of reaching the menopausal transition/natural menopause, after adjustment for age and the number or retrieved oocytes, between women who did and did not have a live birth following their first embryo transfer (OR = 1.3; 95% CI 0.95-1.7). CONCLUSIONS: These results indicate that a low remaining quantity of oocytes, as reflected by a low number of retrieved oocytes at first IVF treatment, is an important predictor of the risk of an early menopausal transition/natural menopause. The quality of the oocytes did not affect the risk of an early menopausal transition/natural menopause once the number of retrieved oocytes had been taken into account. Our findings support the concept that the number of remaining follicles in the ovaries is one of the main aspects of reproductive ageing.

A low number of retrieved oocytes at in vitro fertilization treatment is predictive of early menopause.

OBJECTIVE: To investigate whether women with a low number of retrieved oocytes at the first in vitro fertilization (IVF) attempt have an increased risk of early menopause. DESIGN: Nested case-control study. SETTING: Twelve IVF clinics in the Netherlands. PATIENT(S): Women participating in a nationwide Dutch cohort study (OMEGA) of ovarian stimulation for IVF and subsequent gynecologic diseases (n = 26,428). Each patient who experienced natural menopause at or before 46 years (n = 38) was individually matched to five controls (n = 190) who had not yet entered menopause at the age the patient became postmenopausal. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Relative risk of reaching natural menopause at an early age ( three oocytes). Women who were stimulated with gonadotropins during IVF treatment but did not undergo an IVF puncture because of an anticipated poor response (canceled IVF cycle) had a relative risk of 8.3 (95% confidence interval: 2.9-23.9). CONCLUSION: These results suggest that women with a low number of retrieved oocytes at the first IVF treatment are more likely to become postmenopausal at an early age than women with a higher number of retrieved oocytes. Our study is the first longitudinal study to provide strong evidence for the quantitative aspect of the ovarian concept of reproductive aging.