If you want a deep dive into weighing the risk factors, this paper and those it cites will be a good start; click through for the cited sources.
I think studies of the effect of blue (or other) light sources on melatonin production and the relation of melatonin levels vs risk for these types of cancers is needed to see the whole picture.
That study simply shows a correlation between “ALAN” and cancer rates vs the whole causal chain.
Any study that primarily relies on self reporting is inherently flawed and if you don’t get that then there is no hope in me continuing to argue here.
Yep. Put those questions into Google Scholar and you’ll find much of the work you wish for has been done and published.
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=melatonin+level+cancer+correlation&btnG=
I’m not going to try to summarize the field here, though. I’m just a casual reader like yourself, albeit with a bent toward looking things up in Google Scholar.
Expose it to mass quantities of ‘Blue Light’… that will kill it post haste. . 
Exactly…… :+1: . For any that do not understand, "you can look this stuff up". Google be ur’ friend….
My wife is a clean freak and as a result the light lives ‘in’ the draw instead of on top now.
If you’re asking if I felt affected by the blue light and my sleep then no, there are many other factors that have a far greater impact on my sleep pattern. Besides I honestly think the low output of trits and glow have much less impact than other sources of light in everyday life e.g. room lighting, phones, pc’s…. etc…
Man….is it really matters? I’ve lived throughout the periods of incans, neon sticks, CFL, and now LED. I put whatever lights available in any of my rooms. None of them disrupts my cycle. When I feel sleepy I just sleep. I can easily sleep and drool in my class room, bus, closet, etc… no problem.
Perhaps I have no sensitivity at all?
What really disrupts my sleep cycle is BLF, and I enjoy it. Believe it or not.
[Clemence]
I’m stuck doing on-call work, so why not get my hands dirty in a science thread…
That’s not quite an accurate way to put it. Studies show an association, but the specific cause is not clearly known. The leading theory is the effect is secondary or tertiary due to reduced melatonin production or the reduced amount and quality of sleep that results. There are still lots of open questions.
For example, the methodology of the study Jon posted would be extremely susceptible to confounding factors like there being more LED lights in urban areas, but also more air pollution.
Doubtful. This is one of the problems I have with news reports on most blue light studies (just the news reports, not the studies themselves). They typically fail to clarify that we’re exposed to far, far higher intensities of blue light during the day than what most of these studies look at, which in the latter case is primarily light exposure during our sleeping hours.
The scientists didn’t say “may.” They said there was an association in the data they collected. A newspaper reported that as “may increase the risk of cancer,” which is not unreasonable speculation, but it’s also not very concrete.
The research I’ve found does not agree with you. Color temperature does appear to matter with melatonin suppression at 3900K roughly half that at 6100K. And brightness is at least as much of a factor as color temperature. All of the tests in that study were done at typical office light intensities, except the control was just enough room to find one’s way around.
I’ve not seen any research specific enough to identify the spike at pump emitter’s peak as a specific issue.
There has actually been some research suggesting mixed light causes less melatonin suppression than blue light alone.
Lee 821. As you can probably guess, it will reduce output a modest amount, and visibly change the tint to be more golden.
I see no reason to think a daylight tint like 5600K is a concern for daytime use. 3000K, being a big mismatch in color temperature to the normal ambient source, is not very appealing to me during the day, although I really like it around the house at night.
That is the same study Jon linked to in the first post, just hosted on a different site.
Limited, not flawed. Questionnaires are a common tool for studies on topics for which measurements are impractical, but obviously, well-chosen questions are critical.
In this case, for indoor light level while sleeping, they asked a fuzzy question with 4 possible answers, with the assumption that variation in how different people responds tends to average out in large groups. For outdoor light level, they used measured data. They evaluated both factors separately. Both demonstrated an association.
It is worth noting, however, that the measured data analysis showed a lower association (but still an odds ratio higher than 1) than the self-reported data analysis.
Fwiw, melatonin puts me under and NicOH keeps me under.
Melatonin will start to give me the fuzzies in about 20min, but if I force myself to stay awake through that, forget it. Not even another hit would put me under.
Also, chances are a few hours later when it wears off, I wake up. Hence the NicOH (niacin, 1g) to keep me under.
Best is to just stay “regular”, keep things dark, find something boring to think about.
I take Time Release melatonin.
It helps me fall sleep, and I stay asleep.
(Regular melatonin doesn't keep me asleep.)
Single most well thought out post I have read on this thread. Bravo.
/\ Amen….
Read this thread & you’d think ‘BLF’ stood for Blue Light Fear. . 
And because blue light is a next-of-kin to UV light, keep your pants on when hunting for scorpions at night.
So, what do we actually take away from all this??
- 1. Blue Light DOES NOT cause cancer.
………a. It does/can affect sleep patterns, which in turn affects Melatonin/hormone production; which may make us more prone to develope certain type cancers.
- 2. Is this cause for mass hysteria & wide scale panic??
……….a. NO
- 3. What can we do to possibly avoid this potential ‘Blue Light Death Trap Phenomenon’?? [‘BLDTP’ for short…. ]
Well, without getting overly crazy about it; we can do the common sense things sbslider, pinkpanda3310, & a few others have mentioned:
…………. a. Limit computer, phone, & screened device use a couple of hours before bed.
…………. b. Have a fairly routine sleep time in a dark place. A very faint night light will not hurt…. even if it is Blue most likely.
…………. c.’Don’t Worry, Be Happy’……
The article below from Harvard Medical School is interesting.
Harvard Health Publishing
Harvard Medical School
Harvard Health Letter
Blue light has a dark side
What is blue light? The effect blue light has on your sleep and more.
Updated: August 13, 2018 ……. Published: May, 2012
Although it is environmentally friendly, blue light can affect your sleep and potentially cause disease. Until the advent of artificial lighting, the sun was the major source of lighting, and people spent their evenings in (relative) darkness. Now, in much of the world, evenings are illuminated, and we take our easy access to all those lumens pretty much for granted.
But we may be paying a price for basking in all that light. At night, light throws the body’s biological clock—the circadian rhythm—out of whack. Sleep suffers. Worse, research shows that it may contribute to the causation of cancer, diabetes, heart disease, and obesity.
What is blue light?
Not all colors of light have the same effect. Blue wavelengths—which are beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be the most disruptive at night. And the proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown.
Light and sleep
Everyone has slightly different circadian rhythms, but the average length is 24 and one-quarter hours. The circadian rhythm of people who stay up late is slightly longer, while the rhythms of earlier birds fall short of 24 hours. Dr. Charles Czeisler of Harvard Medical School showed, in 1981, that daylight keeps a person’s internal clock aligned with the environment.
Is nighttime light exposure bad?
Some studies suggest a link between exposure to light at night, such as working the night shift, to some types of cancer, diabetes, heart disease, and obesity. That’s not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad for us. But we do know that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there’s some experimental evidence (it’s very preliminary) that lower melatonin levels might explain the association with cancer.
A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. A mere eight lux—a level of brightness exceeded by most table lamps and about twice that of a night light—has an effect, notes Stephen Lockley, a Harvard sleep researcher. Light at night is part of the reason so many people don’t get enough sleep, says Lockley, and researchers have linked short sleep to increased risk for depression, as well as diabetes and cardiovascular problems.
Effects of blue light and sleep
While light of any kind can suppress the secretion of melatonin, blue light at night does so more powerfully. Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).
In another study of blue light, researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light–blocking goggles to people exposed to regular dim light without wearing goggles. The fact that the levels of the hormone were about the same in the two groups strengthens the hypothesis that blue light is a potent suppressor of melatonin. It also suggests that shift workers and night owls could perhaps protect themselves if they wore eyewear that blocks blue light. Inexpensive sunglasses with orange-tinted lenses block blue light, but they also block other colors, so they’re not suitable for use indoors at night. Glasses that block out only blue light can cost up to $80.
LED blue light exposure
If blue light does have adverse health effects, then environmental concerns, and the quest for energy-efficient lighting, could be at odds with personal health. Those curlicue compact fluorescent lightbulbs and LED lights are much more energy-efficient than the old-fashioned incandescent lightbulbs we grew up with. But they also tend to produce more blue light.
The physics of fluorescent lights can’t be changed, but coatings inside the bulbs can be so they produce a warmer, less blue light. LED lights are more efficient than fluorescent lights, but they also produce a fair amount of light in the blue spectrum. Richard Hansler, a light researcher at John Carroll University in Cleveland, notes that ordinary incandescent lights also produce some blue light, although less than most fluorescent lightbulbs.
Protect yourself from blue light at night
Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin.
Avoid looking at bright screens beginning two to three hours before bed.
If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night.
Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.
The study accounts for various risk factors by using self reported data from a 52 page questionnaire. You should know that the bias from that data set makes this study flawed. The shear number of studies that have had the hypothesis disproven because of self reported data is mind boggling. I will leave it at that.
+100
Yes, forget about science news articles. They misreport what the studies conclude just as often as they get it right. They’re far more interested in clicks than they are interested in accurate reporting.
Go directly to the study. Make sure it is published in a well-respected peer-reviewed journal. Anything else is junk, and likely just a company doing fake studies just to sell you stuff.
Ideally, find a study that has been replicated, which helps eliminate p-hacking effects. A single study on its own, often later turns out to be false. And beware that statistically significant does not necessary mean it has a meaningful effect.
Wait… it doesn’t??
I’m finding this thread interferes with my sleep.
Warm white gang, RISE UP
Yea I no longer use 4000K for my night time EDC. After over a year of experimenting with different night time lights before sleep and its effect on how easy it is for me to fall asleep, I’m now using only 2700K and under. When I started using the E21A 2500K mixed tint as a ceiling bounce lamp, I started actually falling asleep while watching TV! Previously with my higher temp lights (brighter though) I don’t get sleepy and it takes me longer to fall asleep. 4000K and cooler lights also help me stay awake at night so I like them in the day time.