Age of Menopause Varies with Season of Birth
June 1, 2005
Subject: The season in which one is born influences the age of menopause. At least this is what Italian researchers told us last month.
Italian scientists writing in the journal Human Reproduction reported that women born in March reach menopause signifiacntly earlier than women born in October. On average there was around 15 months' difference; women born in October reach menopause at over 50 years compared with less than 49 years for women born in March.
More trivia from Dr. Schor you're thinking: but think about this for a moment Something that happened half a century ago, probably some prenatal environmental factor, can have a measurable effect five decades later. What's this about?
The lead author Dr Angelo Cagnacci said "Our present data seem to indicate that women born in autumn develop better during their prenatal life and are born with a higher number of oocytes than women born in spring," He said the researchers' view was that a prolonged reproductive period with a later menopause was an index of higher embryo quality and ultimately, their quality was passed on to their offspring.
The most obvious difference between a baby born in October and March is prenatal Vitamin D levels. For a baby born in March who was carried during the cold dark winter months, the mom will have reached her low mark for vitamin D levels during pregnancy. For the October baby, the mom's vitamin D levels will be at her peak during the pregnancy.
This makes sense based on older studies on vitamin D and male fertility. Walter Stumpf first suggested that vitamin D is involved with sex and reproduction in 1989. Male genital tissue contains lots of vitamin D receptors but their significance and function remain unknown.
We also know that Vitamin D increases virility, at least in rats. Conception peaks in the summer, when vitamin D levels are highest, and ebbs in the winter, when vitamin D stores are low. Vitamin D deficiency has profound effects on rat testicles, including dramatically reducing spermatogenesis. Vitamin D deficient male rats were 73% less likely to father pups than vitamin D sufficient males. Vitamin D restored virility to vitamin D deficient male rats and should do the same for vitamin D deficient male humans.
Bits of trivia like these can certainly be used to inform our treatment protocols. We already have reasons to increase Vitamin D levels during pregnancy. This new information adds to the existing arguments in favor of supplementation. New for me is the use of Vitamin D in treating male infertility.
[i] Hum Reprod. 2005 May 12;
Season of birth influences the timing of menopause.
Cagnacci A, Pansini FS, Bacchi-Modena A, Giulini N, Mollica G, De Aloysio D, Vadora E, Volpe A.
Department of Obstetrics, Gynaecology and Paediatric Sciences, Gynaecology Units of Policlinico of Modena , Italy .
BACKGROUND: Seasons may influence prenatal growth and future fertility. This study investigated whether season and month of birth influenced the timing of menopause in a group of women attending three Italian menopause clinics. METHODS and RESULTS: Age at menopause of 2822 post-menopausal women (>12 months of amenorrhoea) was stratified by month and season of birth. Mean age at menopause was 49.42 years (SEM: 0.78 years). Menopause occurred earlier for women born in the spring (age 49.04+/-0.15 years) than in the autumn (49.97+/-0.14 years). The earliest menopause was found in women born in March (48.9+/-0.25 years) and the latest in women born in October (50.3+/-0.25 years). The effect of season of birth on age at menopause remained even when considering factors that in our analysis were capable of significantly interfering with the timing of menopause, such as age at menarche, body mass index, smoking habit, level of education and type of job. CONCLUSIONS: Taking into consideration the retrospective design of the study, and a possible recall bias, the present data seem to suggest that environmental factors linked to seasons are capable of interfering with the timing of a woman's ovarian exhaustion by an action exerted in the prenatal period.
PMID: 15890738 [PubMed - as supplied by publisher]
[ii] Am J Obstet Gynecol. 1989 Nov;161(5):1375-84.
Vitamin D (soltriol), light, and reproduction.
Stumpf WE, Denny ME.
Department of Cell Biology, University of North Carolina , Chapel Hill 27599.
Evidence from autoradiographic studies with 1,25(OH)2-vitamin D3 (vitamin D, soltriol) labeled with tritium and from the literature indicates that the steroid hormone soltriol regulates and modulates reproductive processes in the female, as it does in the male. Nuclear receptors for soltriol have been discovered in the uterus, oviduct, ovary, mammary gland, placenta, and fetal membranes, as well as in the pituitary and hypothalamus. Soltriol is recognized as a transducer and hormonal messenger of sunlight, acting as a somatotropic activator and modulator of vital processes for the seasonal and estival adaptation of growth, development, and procreation. Its influence on calcium equilibrium is just one of its many functions to serve this goal. This article s experimental, clinical, and epidemiologic evidence that suggests the involvement of soltriol in the control of reproductive processes, noting its importance for the onset of puberty, fertility, pregnancy, lactation, and probably sexual behavior. Cooperative actions between soltriol and other steroid hormones, especially estradiol, are pointed out.
PMID: 2686450 [PubMed - indexed for MEDLINE]
[iii] Hum Reprod. 1992 Jul;7(6):735-45.
Seasonality in human reproduction: an update.
Rojansky N, Brzezinski A, Schenker JG.
Department of Obstetrics and Gynaecology, Hadassah Hebrew University Medical Centre, Jerusalem , Israel .
A seasonal distribution in human natural conception and birth rates has been consistently demonstrated by epidemiological studies in several geographical areas. Possible hypotheses abound to explain this seasonality. Though a seasonal effect on reproduction is well-documented and has been extensively investigated in mammals, information concerning the influence of seasonal variation and its mechanism on human and primate reproduction is scarce. Recent evidence suggests that deterioration in sperm quality during the host summer in sub-equatorial areas, may result in lower conception rates leading to a reduction in the birth rate in spring. In northern countries, however, in regions where a strong seasonal contrast in luminosity exists, activity of the anterior pituitary-ovarian axis and the conception rate are decreased during the dark winter months. In these areas, inversely, a peak in conception rate during summer leading to a maximum in birth rate in spring has been observed. It is believed that seasonality in the ovulation rate may cause this variability. However, changes in the quality of the ovum or in endometrial receptivity which may lead to a greater waste of ovulated eggs and peri-implantation conceptuses at specific times of the year, have also been suggested. These phenomena might have important implications for in-vitro fertilization and gamete intra-Fallopian transfer as well as infertility in general. The seasonal effects, which may influence primate and human fertility and reproduction and its possible mediators, are critically ed.
PMID: 1323571 [PubMed - indexed for MEDLINE]
[iv] Ann Nutr Metab. 1992;36(4):203-8.
Effect of vitamin D deficiency on testicular function in the rat.
Sood S, Marya RK, Reghunandanan R, Singh GP, Jaswal TS, Gopinathan K.
Department of Physiology, Medical College , Rohtak , India .
To study the effect of vitamin D deficiency on testicular function, 30-day-old male rats were put on a vitamin-D-deficient diet. At 120 days of age, the testicular function of these animals was compared with that of rats of the same age group fed, ad libitum, a diet containing vitamin D and rats fed on a restricted amount of diet with vitamin D. In vitamin-D-deficient rats, there was a significant reduction in the total body weight, testicular and epididymal sperm count and testicular glutamyl transpeptidase activity (an index of Sertoli cell function) as compared to control group rats, but there was no difference in the testicular lactate dehydrogenase activity (an index of germ cell function). Histological examination of the testis in vitamin-D-deficient rats revealed a significant reduction in the Leydig cell count along with degenerative changes in the germinal epithelium. Histological examination of the tibia revealed excess of osteoid in vitamin-D-deficient rats only. On the other hand, in undernourished rats given a normal amount of vitamin D, the only significant change was a reduction in total body weight. These results suggest that vitamin D deficiency retards spermatogenesis by interfering with the function of Sertoli and Leydig cells.
PMID: 1471857 [PubMed - indexed for MEDLINE]
[v] Ann Nutr Metab. 1995;39(2):95-8.
Effect of vitamin D repletion on testicular function in vitamin D-deficient rats.
Sood S, Reghunandanan R, Reghunandanan V, Marya RK, Singh PI.
Department of Physiology, Medical College , Rohtak , India .
Freshly weaned 30-day-old male Wistar rats were fed a vitamin D-deficient diet adequate in calcium and phosphorus for 3 months. On the 120th day of age three different doses of vitamin D were injected intramuscularly into three groups of rats and maintained for another month with water and a normal diet ad libitum. One group was continued with a vitamin D-deficient diet up to the 150th day. One group of animals was killed by decapitation on the 120th day and testicular functions like sperm count in testis and epididymis, testicular glutamyl transpeptidase activity and Leydig cell count as well as body weight were noted. On the 150th day animals of all groups were killed and testicular function was studied. Body weight and testicular function decreased significantly on the 120th and 150th day of age in vitamin D-deficient rats as compared to age-matched normal control rats. Injection of lower doses of vitamin D on the 120th day of age improved testicular function after 1 month whereas administration of a high dose of vitamin D caused a deterioration of the testicular function. The result suggests that retardation of spermatogenesis due to disturbances in Sertoli and Leydig cell function in vitamin D deficiency is reversible and can be corrected by supplementing an optimal dose of vitamin D.
PMID: 7625775 [PubMed - indexed for MEDLINE]
[vi] J Nutr. 1989 May;119(5):741-4.
Vitamin D is necessary for reproductive functions of the male rat.
Kwiecinski GG, Petrie GI, DeLuca HF.
Department of Biochemistry, University of Wisconsin-Madison, College of Agricultural and Life Sciences 53706.
The effect of vitamin D deficiency on the fertility and reproductive capacity of male rats was investigated. Male weanling rats were fed vitamin D-deficient or vitamin D-replete diets until maturity, and mated to age-matched, vitamin D-replete females. Vitamin D-deficient males were capable of reproduction. However, successful matings, i.e., presence of sperm in the vaginal tract of the female, by vitamin D-deficient males were reduced by 45% when compared to matings by vitamin D-replete males. Fertility (successful pregnancies in sperm-positive females) was reduced by 73% in litters from vitamin D-deficient male inseminations when compared to litters from females inseminated by vitamin D-replete males. These results demonstrate that vitamin D and its metabolites are necessary for normal reproductive functions in the male rat.
PMID: 2723823 [PubMed - indexed for MEDLINE]