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Comment by derefr | Hacker News Reader

Implying that a primary causal factor for globally-declining birth rates could be... increased adoption of sunscreen, leading to decreases in libido?

(I'm only half-joking; the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users — are also the countries with the lowest birth rates.)

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I don't get how reduced UV exposure is supposed to be more attributable to sunscreens than to office labors.

Most industrial materials block roughly 100% of UV rays, except viewing windows which allows as much as 1%. Therefore, just staying in any modern building alone cuts down UV exposure by 99% at very least. There is absolutely no way some translucent face painting does that.

> There is absolutely no way some translucent face painting does that.

Wow what a dismissive comment to chemistry and cosmetics.

Just for fun, try take a pic of yourself with a UV camera (or just UV light with some phones), and you'll see it's translucent only to the visible spectrum: https://petapixel.com/2016/05/26/tiny-uv-camera-shows-youve-...

One thing I've recently become curious about, is whether the "UV pigments" in sunscreens are color-fast or not; i.e. whether getting sunscreen on clothing gradually tints the clothing darker when seen in ultraviolet, in the same way that getting throwing a non-colorfast red shirt in with your whites will gradually tint them red.

The Sun Protection Factor(SPF) is defined "a measure of the fraction of sunburn-producing UV rays that reach the skin" when applied as instructed and only over a defined period, usually 2hr[1]. That means there is twofold difference even between a pane of glass(<1% whole body) and correctly applied sunscreen(~2% for 2hr @ SPF50), before taking walls into accounts.

1: https://en.wikipedia.org/wiki/Sunscreen#Sun_protection_facto...

This. Note that even single-layer garments generally don't have a protection factor of 100. Simply being outside in warm weather will give you more UV even if you use sunscreen perfectly--and I don't believe perfect use of sunscreen happens in the real world. I don't care how well you apply it, the protection will be degraded by movement. It will be degraded even more by touching things.

People have been working white-collar jobs indoors behind UV-reflective windows for 50+ years now. Birth-rate decline — especially to below-replacement levels — begins much more recently than that; and is only happening in certain countries.

The set of countries experiencing birth-rate decline is not 1:1 correlated with the set of countries with high/increasing white-collar employment; but, AFAICT, it is 1:1 correlated with the set of countries that have strong avoidance of tanning / strong interest in skin-whitening.

Here is the evolution of the share of blue collar/white collar jobs [0] vs the evolution of fertility rate [1]. I am curious to hear your conclusions from that !

[0] https://publishing.cdlib.org/ucpressebooks/view?docId=ft1580...

[1] https://www.researchgate.net/figure/Historical-Trend-in-US-T...

>but, AFAICT, it is 1:1 correlated with the set of countries that have strong avoidance of tanning / strong interest in skin-whitening.

I'm not seeing that. The countries that are most into avoidance of tanning are probably in Southern Asia, or Asia in general. Their birth rates are not that low, with the exception of Japan, S. Korea and Taiwan.

The middle-class urban populations of these countries really liking lighter skin doesn't imply that the country as a whole will have light skin, though. Achieving that also requires that most of the country be middle-class and urban — being in the set of people who both have time to take care of their skin, and don't spend all day working outdoors in the sun in a way which will unavoidably result in tanning no matter how much sunscreen they use. This is true in Japan / South Korea / Taiwan; but not in these other countries, yet.

You can see it happening in China right now (which also culturally has a preference for lighter skin), as the last few decades of infrastructure build-up have led to a new generation whose parents are lower-class farmers but who are themselves middle-class white-collar workers. My hypothesis would predict a lower birth-rate among this cohort, while the previous generation's birth rate remains high.

Isn't it a common phenomenon that smarter people have fewer children? Once you achieve high education people are more strategic about when, or if, to have children and how many.

> the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users

Isn't it rather more about avoiding skin cancer?

There are a whole host of benefits associated with sun exposure that are reduced by wearing sunscreen.

“Avoidance of sun exposure is a risk factor of a similar magnitude as smoking, in terms of life expectancy.”

https://www.outsideonline.com/health/wellness/sunscreen-sun-...

I'm open to the argument that it's wrong/irrational, but I would wager that - at least in the USA - people wearing sunscreen are doing it to avoid skin cancer more than to avoid tanning.

"...skin cancer kills surprisingly few people: less than 3 per 100,000 in the U.S. each year. For every person who dies of skin cancer, more than 100 die from cardiovascular diseases."

Personally, I'm from the UK and don't worry about skin cancer. If I was in Australia or some climate I'm not adapted for then I'd be concerned.

kills surprisingly few people: less than 3 per 100,000

Yet the impact on quality of life is huge. Using the same US numbers [0], comparing directly-attributable deaths against life years lost (disability-adjusted life years):

- melanoma: 2.2 vs 64.8

- squamous cell carcinoma: 0.8 vs 26.6

- basal cell carcinoma: 0.2 vs 51.2

[0] https://pubmed.ncbi.nlm.nih.gov/33852922/

Fair cancer impact comparisons. But the point was that increased sunshine can reduce cardiovascular issues so you'd need to look at incidents and impact for heart attack, stroke, etc.

I am not certain how much credibility this publication deserves.

It's not scientific by nature, it focuses on outdoor activities, which is only a tangent topic, the author has no bio, there is little to no bibliographic references.

Perhaps I should've mentioned that this quote was taken from a research publication.

"In a 2016 study published in the Journal of Internal Medicine, Lindqvist’s team put it in perspective: “Avoidance of sun exposure is a risk factor of a similar magnitude as smoking, in terms of life expectancy.”"

The quotation is from a well known paper in the field cited over 100 times according to google scholar: https://doi.org/10.1111/joim.12251

It was an observational study of 30k women over two decades, so very good statistical power.

> As compared to the highest sun exposure group, the mortality rate was doubled (2.0, 95% CI 1.6–2.5) amongst avoiders of sun exposure and increased by 40% (1.4, 95% CI 1.1– 1.7) in those with moderate exposure. We found that the assumption of proportional hazards seemed reasonable.

So at least among Swedish middle aged women, you are twice as likely to die if you avoid the sun, vs. if you are exposed more to the sun, controlling for factors like income, education, smoking, BMI, and exercise.

It was not a RCT, but then almost no studies of all cause mortality are.

A smaller case study of 500 melanoma patients (https://doi.org/10.1093/jnci/dji019) also found that "sun exposure is associated with increased survival from melanoma."

I think sudden and extreme sun exposure, i.e. "staying in an office all year and then going on the beach for 9h on vacation" definitely requires sunscreen, but consistent and moderate sun exposure at a rate that your body can tan and adjust to is probably a net positive for everything from circadian effects to mood and mortality, even accounting for skin cancer risk.

While American and European sunbathers tend to seek the perfect tan, many Indian and East Asian women avoid it at all costs, through sunscreen and a whole bevy of skin-lightening products:

https://www.bbc.com/news/magazine-18268914

https://www.sixthtone.com/news/1005927/chinas-quest-for-fair...

Such standards of beauty are quite old and largely predate Western colonialism. My impression is that they were often linked to caste or class, where higher-class people spent more time indoors while lower-class workers spent more time out in the sun.

This cultural difference is the source of much amusement for the Indian spouse of my European coworker. When they vacation in Europe all the ladies on the beach want to tan, and when they visit India it’s the other way around.

Yep,

In many caste-esque societies, having a darker tone is a sign of having to work outside, thus of lower class.

This happens a lot in the Philippines, for example. With a ton of skin lightening products.

Being chubby and pale was desirable when the poor had to toil away outside and didn't have enough food to eat.

Being thin and tan is desirable today when the poor have to toil away in offices and don't have enough free time to go to the gym or take vacations in warm places.

Chubby and tan signifies strength and wealth. Thin and pale yet rich is a contradiction, adds mystique and suggests power.

Ha You physically fit, hardy to the elements, thin, muscular, used to hardship, leathered and hardened skin, emotions, grit and resentment who is only capable of using farm implements, what power do you have against me and my court of beautifully adorned elite, who weild the master-craft blades of our ancestors!? HA

'Farmer-class': Well, we have awareness, darkness, and an array of farming tools as weapons, such as Kusari Gama (sickle), nun-chuck (rice thrashers), the modern police baton is a farmers implement...

Also, we know how to fight in close quarters, such as your Rice Palace, and as such we have short, straight, nible blades and Iai KPIs show that our blades are superior in cramp enclosures, as opposed to your blades, which the curve is to assist in the blade length for the cut as you pull, however, in close quarters, your large exaggerated movements are a detriment....

Also, We know that our blade is a tool thus, we will flick dirt at you with it, because you see your sword as an extension of your soul, and will not let it touch earth.

Being tan is desirable for the upper class, because they're trying to avoid being seen as middle class "toiling away in offices", and don't particularly care about being confused for lower class.

Being pale is still desirable for the middle class themselves, though, as they're trying to avoid being seen as lower class (tradespeople, farmers, etc).

Also, thinness is actually a middle-class obsession, because it's the lower class who "don't have enough free time to go to the gym or take vacations in warm places." The upper class don't care what their bodies look like, as they all know that they and everyone else in the upper class can afford to "throw money at the problem" (plastic surgery et al), and so how healthy you look is no longer a good signal for how healthy you actually are. (Instead, they tend to judge your genetic fitness — when they care about that sort of thing — by the health of your lineage, going back several generations. Which is one reason royals/nobles make a big deal of keeping track of that.)

>".... farmers..."

[Dystopian Aside]: I have been saying for a very long time (rightly/wrongly), but always been laughed at; "In the future, the most valuable people will be farmers"

I was laughed at.

However, look where we are headed. Right now, today ; BGates is not only one of the most famous and richest people on the oblate spheroid, he is also the richest "farmer"[0] in the world.

The "farmer" ([0]:pharm-er) who masters lab-grown civilization-supporting-scale sustenance production will be the richest in the galaxy.

Ever try to corner the galactic wheat production in Trade Wars on BBSs in the 1980s? Yeah - we are at stage zero of seeing that in action, and it wont be pretty.

> My impression is that they were often linked to caste or class, where higher-class people spent more time indoors while lower-class workers spent more time out in the sun.

I'm no expert on the topic, but i heard people refer to this sort of social symbol and discrimination as "colorism".

For anecdote, in France, "sang bleu" (blue blood) used to refer to the nobles and higher classes, as they didn't work the fields, and their thin and pale skin let see through the blue-looking veins. From what i hear, it appears before the revolution this biological distinction was formally racialized: the higher classes with their never-sighted "blue blood" was another "race" as the lower peoples whose spilled blood we could confirm was red.

I use it to avoid burns?

Cultural expectations on tanning come down to signs of wealth.

Industrialized societies most work is performed indoors, most people only tan during leisure time. Thus a tan is an indication of having leisure time and is looked upon positively.

Societies that are not industrialized most work is performed outdoors, leisure is generally indoors. Thus the absence of a tan is an indication of wealth and is looked upon positively.

Note that this lags behind reality, many places have industrialized but their perception of tans is still negative. My wife is Chinese and I sometimes joke that she's half-vampire because of how sun-avoidant she is.

If that’s the case then it’d come as a relief. But I doubt it. Realistically the fact wage to housing/health/education/childcare is a bigger contributor.

Provided how people apply sunscreen, I doubt it. Not exactly translatable, but there was no effect on vitamin D levels in people using sunscreen: https://pubmed.ncbi.nlm.nih.gov/30945275/

It is probably birth control in the water supply that are causing birth rate declines.

That has been thoroughly studied and debunked. Just one example of many:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2854760/

Add to this the fact that less than 1% of the estrogen in the water supply is from The Pill.

Yes. I'd be more worried about estrogen in meat.

https://ascopubs.org/doi/abs/10.1200/jco.2010.28.15_suppl.15...

That paper used predicted estrogen instead of measuring estrogen. I wouldn't say it has been studied at all based on that link.

> (I'm only half-joking; the countries that are most obsessed with keeping skin white — and so are likely the highest sunscreen users — are also the countries with the lowest birth rates.)

Obsession with keeping skin white is not something I normally see associated with South Korea, Singapore, or Bosnia and Herzegovina.

Have you ever tried to buy sunscreen in Asia?

Obsession with keeping skin white has been a major trend in Korea for a long time, have you seen all the weird hats and face masks that ajummas wear in order to reduce sun exposure?

Can't speak much for Bosnia but in most of South East Asia it's nigh on impossible to find any body wash, sunscreen or moisturiser without whitening products added.

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