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Sunbathing IS allowed

Sunbathing IS allowed!(Dutch original title: Zonnen mag)

A new vision on sunlight and health

by Dr. Han van der Rhee

Cover text

Every spring and summer we are confronted with media messages (media-berichten) about the dangers of the sun, particularly regarding skin cancer. Usually these messages are one-sided, only mentioning the negative effects of sunlight. Besides, most of the time they are unnecessarily alarming.
In Zonnen mag Han van der Rhee describes in a very accessible way all scientific data known about both negative and positive effects of sunlight on our health. He describes effects known for many years, such as the favourable effect of sunlight on skin-, bone- and muscle disease and on depression. From more recent research it becomes increasingly obvious that sunlight may have a preventive effect on colon-, breast-, and prostate cancer.
The scientific information is interspersed with case histories and (personal) anecdotes and cartoons .
Van der Rhee concludes in this surprising book that it is very well possible to enjoy the sun in a healthy way.

During the first three months of its appearance this book received massive attention of all media in The Netherlands.

About the writer

Han van der Rhee has been a dermatologist for more than 31 years. Since 1989 he has been active in the Netherlands in many advisory committees drawing up medical directives concerning the diagnosis, treatment and prevention of skin cancer. He is an advisor of the National Cancer Foundation, combining wide experience as a doctor with long-standing scientific interest, resulting in the publication of many papers in renowned international scientific journals on (skin) cancer and sunlight.


About the book

In the Introduction the author describes both his personal and scientific motivations for writing this book. In 1989 he organized an attention-drawing campaign against sun exposure and for many years he warned publicly against the dangers of sun exposure. His reasons for the change in his opinion are explained.

Chapter 1

Good news under the sun (pp. 12-29)

The chapter starts off with a personal story. Because of his scientific papers on the favourable effects of sunlight,Van der Rhee was invited in 2008 to give a lecture for the Dutch Academy of Dermatology on "controversies about the role of sunlight in cancer". The effect of the lecture was like that of cursing in the church. A parallel is drawn with the research of Barry Marshall, who was derided for his research showing that the cause of gastric ulcers is an infection with Helicobacter pylori instead of stress.

In 1941 the American epidemiologist Frank Apperly found that cancer mortality in the USA diminished from North to South, suggesting that sunlight might have a preventive effect on cancer. In 1956 the Australian epidemiologist Henry Oliver Lancaster found that in areas with much sunlight the mortality of melanoma was higher than in areas with less sunlight. The former finding fell into oblivion, while the latter was widely accepted.
In the rest of the chapter all recent overwhelming research on the preventive effect of sunlight on cancer is extensively described, interspersed with some histories of patients who harmed themselves by too little exposure to sunshine or, on the other hand, who benefited from overcoming their fear of sunlight.
Finally it is concluded that sunlight most likely diminishes the risk and mortality of colon-, prostate- , breast cancer and non-Hodgkin lymphoma, while it should be borne in mind that the mortality of these types of cancer is about 20 times as high as the mortality of skin cancer. This conclusion might affect the kind of advice relating to sunbathing given to the general public.

Chapter 2

More good news (pp. 30-48).

In this chapter some well-known positive effects of sunlight on bone- muscle- and skin disease are described. In addition the effects of (sun)light on our state of mind and the curative effect on some types of depression is elaborated. Finally the recent research on the relationship of sunlight, vitamin D and multiple sclerosis is set out.

Again the scientific information is alternated with illustrative case histories.

An example of a case history is given below:

In 1997 Mrs. C. visited my office for the first time. At that time she was 73 years of age. She had some spots on her forehead that alarmed her. They appeared to be so-called actinic keratosis spots, innocent skin lesions caused by life-long sun exposure. I told her that, if they were not treated, there was a small chance that these spots could become squamous cell cancer, one of the three types of skin cancer. Next I treated them with liquid nitrogen and they healed without leaving any scar.
In 2007 I saw her again: now she had a small tumor on her left jaw. It was a basal cell carcinoma, an innocent form of skin cancer. It was cut out under local anesthesia and the cosmetic result was very nice.
She told me that 1993 she had broken her left fore-arm. In 2006 she broke her right arm and the family doctor gave her calcium tablets and some medicine against bone resorption. In 2007 without any noticeable trauma she broke her left fore-arm again. In the spring of 2008 she got terrible pains in her back. She was X rayed and these pains appeared to be caused by collapsed spines. Her length diminished 20 centimeters in relatively short time. She was referred to a specialist for internal diseases, who found an extremely low vitamin D level in her blood. Consequently he prescribed her vitamin D tablets.
When I asked Mrs. C. how often she was in the sun she responded: "Since 1997 I have never been in the sun again; even when in company I always stay in the shade." Out of fear for skin cancer( she had read that you can die from a squamous cell carcinoma) she was living like a mole causing her vitamin D deficiency and constant back pain.

Chapter 3

Sunlight and skin cancer (pp. 49-69)

Here the different types of skin cancer are described in relation to their association with sunlight.

The chapter begins with a personal anecdote:

In the nineties, because of my publicly known interest in the subject, I was frequently asked as a speaker on skin cancer and sunlight. Many times I was invited by both catholic and protestant regional women's associations. Usually I was supposed to entertain them during the whole evening for the fee of a bottle of wine. Sometimes it was difficult to keep their attention and I found out that when I showed them horrible pictures of skin lesions this helped a lot. Therefore after a while I always started my speech with two highly imaginative case histories.
The first history concerned a man in his sixties who partially earned his cost of living by selling books and magazines door to door. It was quite unlikely that his business was very successful since his face was largely covered with terrible ulcers and crusts. About half of his face showed (precursors of) skin cancer. From the pathology lab the cancers appeared to be innocent forms: they all were basal cell carcinomas. With a combination of treatments (surgery, radiation therapy and treatment with liquid nitrogen) the result was unexpectedly good. Hardly any sign of a skin disease or effect of the treatment was visible. I expect that the sale of his books must have increased enormously.


After that I presented a case of a young mother with a tiny brown lump on her right upper leg. On the picture shown the difference with other moles on her leg was hardly visible. The lump was cut out and it appeared to be a melanoma. Therefore a re-excision was necessary. In her case the cosmetic result was very nice too.

Hardly one year later I discovered a suspicious lymph node in her right groin. One year later she died of metastases of her melanoma. For a dermatologist, who is not often confronted with death, an impressive experience. The ladies of the women's associations were impressed by these case histories and they were as quiet as a mice.

These case histories show that it is difficult to speak of skin cancer in general terms, which is often done in the media. Skin cancer consists of three different types, which look different, behave completely differently and also have a different relationship with sunlight. Melanoma (about 8% of all skin cancer cases) is caused by intermittent (irregular) sun exposure, particularly when sunburn occurs. Chronic (regular) sun exposure is not associated with risk of melanoma and some studies even show a small risk-reducing effect of this type of exposure. People with an outdoor profession have the smallest risk of getting a melanoma. Marianne Berwick, professor at the University of New Mexico found that melanoma patients with signs of chronic sun exposure had a slightly lower risk of dying from a melanoma than patients with less sun exposure. This finding was also reported by other research groups. In addition several investigators found that when melanoma patients were diagnosed and treated at the end of summer (when vitamin D levels are high) there was a slight, but significant, better survival rate compared with patients who were diagnosed and treated at the end of the winter (when vitamin D levels are low). Melanoma is the most aggressive type of skin cancer. About 18% of the patients die. Early recognition and treatment is very important for a good prognosis.

Squamous cell carcinoma (about 10% of all skin cancer patients) is related to all types of sun exposure, particularly to chronic and professional exposure. This type of skin cancer is relatively harmless. In only 3% of the patients (mainly persons with an immune deficiency and those with a very long patients delay) have metastases.

Basal cell carcinoma (more than 80% of all skin cancer patients) is caused mainly by intermittent sun exposure and in a lesser degree by chronic sun exposure.
Generally, this most common type of skin cancer is harmless. To prove this view, the author interviewed 30 of his colleagues. He asked them whether, if they could choose, they preferred a basal carcinoma or a different type of cancer. They all preferred to have a basal cell carcinoma. Next he asked to choose between basal cell carcinoma and a relatively harmless disease, like diabetes or hypertension. All of them chose the basal carcinoma. Next they were asked whether they preferred a basal cell carcinoma above a skin disease like psoriasis, eczema or vitiligo. Almost all dermatologists preferred a basal cell carcinoma. About one third of the interviewed dermatologists ( in particular the older dermatologists) even preferred an basal cell carcinoma above a large plantar wart.


Chapter 4

Other disadvantages of sunlight (pp. 70-82)

Skin ageing can be intrinsic ageing and extrinsic ageing. These processes are explained. Extrinsic ageing is mainly caused by sun exposure. However, in contrast, sun exposure might have a positive effect on internal ageing: persons with a low blood level of vitamin D (mainly caused by lack of sun exposure) appeared to have a 5 years higher biologic age than persons with high vitamin D levels (mainly caused by sun exposure).

Some skin diseases can be caused or aggravated by (sun)light: polymorphic light eruption (the so-called sun allergy), skin eruptions caused by a combination of sunlight and medicines plant, cosmetics etc..

There is some research suggesting that the eye diseases pterygium and some types cataract may be caused or aggravated by sunlight.

Two rare internal diseases may be aggravated by sunlight: porfyria and LE (lupus erythematosus). The nature of these diseases and their association with sunlight are explained.

Chapter 5

Sunbeams (pp. 83-95)

In this chapter some data about the sun, sun beams, the ozone layer and sunbeams reaching earth are described. It also contains a section on artificial UV light.

Chapter 6

The effects of sunbeams (pp. 96-112).

In this chapter the mechanisms of various positive and negative effects of UV-, infrared-, and visible lights are elaborated. This in relation to skin cancer, the prevention of cancer, the effects on the immune system and the day/night rhythm. Much attention is given to the metabolism, the effect of higher and lower dosages and blood levels of vitamin D. The presently advised blood levels of vitamin D are questioned.

Chapter 7

A wise exposure to sunlight (pp. 112-128)

This chapter starts off with some quotes from daily journals, warning alarmingly about the dangers of the sun, stating that sunbathing can be extremely dangerous, that there is an ever increasing epidemic of skin cancer which is getting worse and worse. In these quotes it is frequently said that this increase of skin cancer is caused by having too much sun. The author queries some of these statements.

The next section deals with some data known from anthropology and archaeology.
The ancestors of all inhabitants of middle and northern Europe were Homo sapiens. Sixty to fifteen thousand years ago they emigrated with a dark skin from East Africa. In Europe their skin was too dark for a sufficient vitamin D level. Low levels of vitamin D gave problems with their bones, muscles and fertility. Consequently, according to the laws of Darwin, the palest variants of the Homo sapiens had the best chances of survival. In this way we gradually developed from dark Africans into pale Europeans. Anthropologists think that it takes our skin 10 -15.000 years to adapt to the climate of the country of immigration and to get the healthiest skin colour. They believe that our skin is very well adjusted to our climate. Our ancestors, however, became gradually less exposed to sunlight by living increasingly indoors. Recent measurements found that our face and hands are exposed only to 2-3 percent of the available UV light. About a quarter of this during our holidays. It can be concluded that we do not expose ourselves too much, but rather too little to the sun and if we expose ourselves we do this in an extreme way with a skin which is not yet adjusted to sunlight. This behaviour causes many sunburns.

Possibly the warnings against too much sun even aggravate the increase of the incidence of skin cancer. Regular sun exposure with some restrictions might be a better strategy for the prevention of skin cancer. In this way one can not only prevent skin cancer, particularly the most life-threatening type melanoma, but also benefit from the proven and the probable benefits of the sun.

In the next section question marks are placed with the so-called skin cancer epidemiology. Although there is a real increase in diagnoses of skin cancer, some of this increase can be ascribed to the growing awareness of people that they should go to their doctor with suspected skin lesion leading to the diagnosis of very innocent and possibly biologically benign forms of skin cancer. In addition there is scientific evidence for over-diagnosis and an increasing number of false-positive diagnoses.

Next the evidence for the use of sunscreens in the prevention of skin cancer is questioned.

Finally the author gives his opinion on sunning wisely, which is summarized as follows:
Enjoy the sun without exaggeration and without burning. This type of behaviour is pleasant and healthy. If you have a suspected skin lesion do not hesitate to consult your family doctor.


Acknowledgements 129

Appendix: how to recognize skin cancer 131

Glossary 134

Sources 141

Index 152

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