UV-radiation can affect hormone levels of postmenopausal women negatively

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UV-radiation can affect hormone levels of postmenopausal women negatively and this may contribute to several health issues. The concentration of estrogens in the blood affects a woman’s health in many ways.

For example, estrogens contribute to a strong bone structure and help wounds heal more quickly.

“When a woman reaches menopause, we see the levels of oestrogens decline and an increase of other hormones, called gonadotropins”, says Kai Triebner at the University of Bergen.

For several years, he has studied the hormonal balance of women in relation to menopause: What effects changing hormone levels have on health and wellbeing, how environmental factors affect hormone levels and how to estimate the progress of the menopausal transition, among other things.

Triebner’s earlier research has shown that menopause affects women’s lung function negatively, and that access to green spaces may postpone menopause. Recently, he has investigated how UV-radiation affects the level of estrogens and gonadotropins.

The article is published in Maturitas.

Too much sun may cause health problems

Triebner and his team have collected data from 580 postmenopausal women across Western Europe, participating in the European Community Respiratory Health Survey (ECRHS). Using satellite data, they have developed a model of how much UV-radiation the women have been exposed to, depending on their place of residence.

They also asked the women to state how much time they spend in the sun; which parts of the body are usually exposed and if they use sunscreen.

“The basis for the model is a validation study from ISGlobal in Barcelona where they have used a necklace to measure UV-radiation exposure” explains Triebner. This resulted in a model that gives the researchers a good measure of the individual UV-exposure for every participant included in the study.

They have also measured the hormone concentrations and compared that to the UV-exposure during the month before: They found that participants who were most exposed to sunlight had lower levels of oestrogens and more gonadotropins compared to those exposed to lower levels of UV-radiation. This may cause health problems:

“A low estrogen level and a high level of the other hormones increases the risk of osteoporosis, cardiac diseases, and neurodegenerative diseases, such as Alzheimer’s,” says Triebner.

“Use sunscreen!”

The women included in the study were from Denmark, Norway, Sweden, Iceland, France, and Spain, in other words a cross segment of Western Europe. Women who used hormonal medication where excluded from the study.

The country of residence of the participants did not seem to cause a great difference in UV exposure:

“If you live in Spain, you preferably stay inside during the sunniest hours, but if you live on the rainy coast of Norway, you use every possibility to get a tan”, says Triebner.

The researcher says that sun exposure needs to be carefully monitored after menopause, as it is potentially harmful, but at the same time, UV light is needed to keep the vitamin D level up and stay healthy.

“How much vitamin D you need varies from person to person and where you live. As a rule of thumb, ten to fifteen minutes a day in the sun with your face and lower arms exposed is recommended”. If you exceed this, you should wear sunscreen, regardless of whether you sunburn easily.

“When you get a sunburn, you are already far above the recommended level of UV-radiation, and at an increased risk of developing melanoma”, reminds Triebner.

“We have only dipped our toe in the water” This method of determining UV-exposure is unique, says Kai Triebner:

“As of today, there is no study that looked into this with greater detail”, he confirms.

According to Triebner, one has just begun to see what effect UV-radiation has on women’s hormonal levels and reproductive ageing. The researchers have identified an association between the dose of UV-radiation after menopause and the concentrations of hormones in blood.

They do not yet know what effect the sun has on the hormone balance of younger women:

“UV-radiation might affect when in life you reach menopause. But it might also be plausible that UV-radiation has a beneficial effect on the hormone balance before menopause.

As researchers we have only ‘dipped our toe in the water’. There is still much to investigate”, concludes Triebner.


The ever-popular Vitamin D (VD) is commonly known as the «sunshine vitamin» [1] and (like sunshine) is implicated to positively alter mood. VD itself is known as a secosteroid hormone, recognized as a neuroprotective factor which plays a role in brain development [2, 3].

VD is involved in a range of important physiological processes, such as in promoting cell growth and differentiation, facilitating immunomodulation regulation, and being involved in neurotransmission, and anti-inflammatory effects. On the other hand, low concentrations or deficiency of VD have been associated with various mental and neuropsychiatric disorders, consisting of psychotic and mood disorders, autism, and cognitive decline [2, 3].

No doubt, depression plays a very important role in women’s disease-related disabilities. The current paper will review and summarize recent research on the relation of VD levels and the epidemiology of depression in women. In this paper, we will outline relevant studies about the relationship between VD and depression in women in an attempt to provide useful recommendations in terms of future scientific questions that need to be addressed in this research area.

VITAMIN D AND LIFESTYLE
Vegetables, herbs and fruits can contribute to a person’s health in terms of the levels of VD2, while meat and fish (especially fatty fish) can contribute to VD3. This means that VD levels are influenced by environment and lifestyle. However, except for fatty fish, relatively few foods naturally contain large amounts of VD [4].

A recent meta-analysis of 31 studies (with 79366 individuals) showed that some genetic factors might also modulate VD levels [5]. The findings of this meta-analysis were also suggestive of a relatively small heritability rate for VD levels, but overall indicated that modifiable environmental factors are the main determinants of VD levels.

Ultraviolet sunlight synthesis of VD depends on the season, latitude, and amount of skin exposure [6]. Levels of VD vary seasonally, with deficiency more common in winter and at higher latitudes, reflecting ambient levels of sunlight [6], as well as in urban settings, owing to lifestyle choice and lower sunlight exposure [7].

Due to difficulties of darker skin to absorb sunlight, Black and Asian populations are more likely to be affected by lower levels of VD and related negative consequences on health [8]. In most parts of the world, during sunny months optimal levels of VD (approximately 1.000 IU per day) can be achieved by minimal (5 to 15 minutes depending on the level of sun) sun exposure of face, arms, and hands without sunscreen [9].

The liver transports consumed VD2 and VD3 with the use of chylomicrons. Then, it binds to proteins in plasma, in turn, carry the VD3 which originates from sunlight exposure [10]. VD is synthesized predominantly endogenously (approx. to 90% of the total VD in human body).

In the skin, the ultraviolet light transforms 7-dehydroxycholesterol (provitamin D) to pre-vitamin D, which under the influence of body temperature spontaneously isomerizes to cholecalciferol (VD3). Approximately 10% of total body VD is taken orally (ergocalciferol and cholecalciferol).

VD is transported via VD-binding protein to the liver, where it is hydroxylated to 25-hydroxyVD [9, 10]. The next step in VD activation is hydroxylation of 25VD by the enzyme 1α – hydroxylase (CYP27B1) to 1,25-dihydroxyvitamin D (1,25VD), which is the active VD metabolite.

This process occurs predominantly in the renal tubules. In addition, non-renal CYP27B1 was detected in skin (basal keratinocytes, hair follicles), lymph nodes (granulomata), colon (epithelial cells and parasympathetic ganglia), pancreas (islets), adrenal medulla, brain (cerebellum and cerebral cortex), prostate epithelial cells and placenta (decidual and trophoblastic cells), indicating the wider significance of the VD metabolites [11]. Finally, 1,25VD is inactivated by the enzyme 24-hydroxylaze.

1,25VD exerts its effect via the VD receptor (VDR), which is detected in all human organs [10-12]. 1,25VD binds to VDR, the complex forms a heterodimer with the receptor for retinoid X (RXR) within the nucleus. The 1,25VD-VDR-RXR complex binds to VD reacting elements, modulating gene expression [12, 13].

Dietary intake of VD rich foods is also important for maintaining healthy 25(OH)VD levels, especially when direct sun-exposure is low. VD status is being evaluated via the serum level of 25(OH)VD – the metabolite formed in the first hydroxylation in the liver, due to its longer half-life (approximately 3 weeks), compared to the active metabolite 1,25(OH)VD (4 – 6 hours) [15].

There is a consensus among experts that we should revise the recommendations for VD intake of 200-600 IU per day which is currently in place, as these cannot adequately prevent VD insufficiency [14, 15]. A healthier recommendation for VD related food intake for individuals with low levels of sunlight exposure would range from 800 to 1000 IU per day.

This would subsequently also affect 25(OH)VD levels to be more in the preferred range (30-40 ng/ml) and affect VD related health consequences [15].

reference link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327938/


Original Research: Open access.
Ultraviolet radiation as a predictor of sex hormone levels in postmenopausal women: A European multi-center study (ECRHS)” by Kai Triebner et al. Maturitas

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