CRP is a protein that links stress, emotional, and socioeconomic cues to chronic inflammation and heart disease. Keep reading to find out about the main lifestyle, dietary, hormonal, and other causes of high CRP that are rarely talked about.
Below are some of the causes that have been associated with higher CRP levels. Keep in mind that CRP can be elevated due to underlying medical conditions that need treatment. If your CRP is high, work with your doctor to get an accurate diagnosis.
Lifestyle Causes of High CRP
1) Sleep Disturbances
There is an established, yet complex, relationship between CRP and sleep. Excess sleep, insufficient sleep, frequent napping, and infrequent napping have all been linked with elevated CRP, but these relationships seem to depend on both night and daytime sleep patterns [1, 2, 3].
Insufficient sleep has been linked to inflammation.
For example, scientists have found that CRP increases with both sleep deprivation and poor self-rated sleep quality in a dose-dependent manner [1].
In one study, both total (88 hours) as well as partial (4.2 hours during 10 consecutive nights) sleep restriction significantly increased blood levels of CRP [4].
Another study showed that CRP was elevated immediately after sleep restriction, and since this protein has a half-life of 19h, this elevation was sustained even after two days of recovery sleep [5].
On the other hand, several investigations have linked oversleeping (≥9 hrs/night) with higher CRP in those with Obstructive Sleep Apnea and type 2 diabetes [1]. It’s quite possible that longer sleep time doesn’t cause higher CRP, but rather people with inflammation (and therefore higher CRP) need more sleep.
Elevated levels (>3.0mmol/l) of CRP were observed in both ≤6h and ≥10h sleep in a study of over 2.5k aging men [6].
The relationship between daytime naps and CRP is ambiguous. In one study, self-reported nappers had increased CRP, and the authors suggested that frequent naps may actively elevate CRP, possibly via enhanced blood pressure upon waking [1].
On the other hand, a recent investigation focusing on young adults who nap infrequently reported that IL-6, an inflammatory molecule that usually increases together with CRP, increased following sleep deprivation but decreased after subsequent naps [1].
Interestingly, one study looked at sleep-wake concordance i.e. whether couples are awake or asleep at the same time throughout the night. Men and women with higher sleep-wake concordance had lower CRP values [7].
2) Smoking
Cigarette smoking increases CRP [8, 9, 10, 11].
3) Stress
CRP is elevated in chronic stress and may be the link between stress and low-grade inflammation-related diseases.
Scientists found that both psychological and social stress significantly impacts CRP [12]. In a study that examined job stress and CRP levels among Chinese workers, effort, overcommitment, and effort-reward imbalance were all significantly correlated with higher CRP; while rewards were significantly related to lower CRP [13].
A link was found between higher CRP levels, chronic stress, and burnout in women with psoriasis [14].
A study suggests that people who engage and work on resolving their issues (positive engagement coping) may have lower CRP in the context of interpersonal stress (e.g., arguments with parents or siblings, conflicts between adults in the home, friendships ended) [15].
4) Socioeconomic Factors
Researchers found a link between CRP levels and many social and economic factors, which, in many cases, translated into chronic stress.
Studies agree that as neighborhood and family’s socioeconomic status increases, CRP tends to decrease [16, 17, 18].
In one study of over 13k children, children whose parents had less than a high school degree had 35% higher CRP on average than those with a parent that graduated college; also, poor children had 24% higher CRP on average than those with higher family incomes [19].
Another study found that children living in neighborhoods with high levels of poverty or crime tended to have elevated CRP levels compared to children from other neighborhoods [20].
In a Swiss population, a linear association was found between education and CRP (more education = lower CRP) [21].
Furthermore, scientists found that both higher education and household income predicted lower CRP levels after 13 years on average [22].
Depending on the study, associations with CRP and race were observed, or not found [23, 24].
Being married is weakly associated with lower CRP level [25].
Several studies have demonstrated that women may have higher levels of CRP compared to men [26].
Among heterosexuals, women had higher levels of CRP than men. However, sexual-minority men had higher levels of CRP than heterosexual men and sexual minority women. Lesbians had lower levels of CRP than heterosexual women [26, 27].
Finally, research suggests that those with more children may have higher CRP than individuals without children or those with fewer children. This association could reflect the associations between high CRP and higher economic stress, exhaustion, and chronic stress [28].
5) Substance Abuse
Scientists have found that CRP levels tended to be higher in the presence of nicotine, alcohol, and cannabis use and nicotine dependence [29].
A U-shaped cross-sectional relationship between CRP and alcohol consumption is widely documented. Whereas alcohol in moderation appears to be beneficial, alcohol users showing abuse or dependence have elevated CRP [29].
6) Altitude
While a short-term stay at moderate altitude (2,590 m) can decrease CRP levels, higher altitudes increase CRP and systemic inflammation [30].
Circulating CRP increases in response to low pressure and low oxygen conditions (hypoxia) at high altitude [31, 32].
One study following a 2-week mountaineering expedition (at 3,200 – 3,616 m) found that participants had increased CRP levels during the expedition [33].
7) Extreme Cold
Studies have found that in temperatures below 0°C, CRP level increases with decreasing temperature. A reverse association, however, was observed above 0°C [34].
Dietary Causes of High CRP
8) Saturated Fatty Acids and Trans Fats
There is a potential link between saturated fatty acids (SFA) and CRP levels [35].
Lauric and myristic acids and high saturated/polyunsaturated fatty acid (SFA/PUFA) ratio have been associated with elevated CRP in men [36].
A study of over 700 nurses showed that those with the highest trans fat intake had blood levels of CRP that were 73% higher on average than those with the lowest intake [37].
9) Vitamin Deficiency
Elevated CRP has been associated with vitamin D deficiency in city-dwelling seniors [38].
High CRP levels were also linked with prenatal vitamin A deficiency. Similarly, children with lower retinol (vitamin A) levels were more likely to have high CRP levels in one study [39, 40].
The same may apply to adults as well. In sub-Saharan Africans, vitamin A-deficient people were at a much greater risk of high CRP [41].
Additionally, CRP levels were higher in both older people and young women with lower vitamin K levels [42, 43].
Hormonal Causes of High CRP
10) High Leptin
Leptin, the “satiety hormone,” increases CRP production in the liver and blood vessels. High leptin levels are linked with obesity, overeating, and inflammation-related diseases [44].
People with high blood leptin and CRP are more likely to gain too much weight. Even when leptin is given to people as a medication, it increases blood CRP levels [45].
On the other hand, studies suggest that CRP can bind leptin in the blood. Therefore, high CRP levels may restrict leptin and cause leptin deficiency in the hypothalamus which, in turn, makes losing weight and fighting off infections a struggle [45].
11) High Estrogen
Estrogen therapy increased CRP levels in women. Additionally, postmenopausal women using hormone replacement therapy (HRT) tend to have higher CRP levels [46, 47, 48].
Underlying Infections and Inflammation
12) High Cytokines
CRP production is regulated by interleukin-6 (IL- 6), interleukin-1b (IL-1β), IL-17 and tumor necrosis factor-α (TNF-α) [49, 50].
These cytokines can be produced in response to bacterial infection, tissue damage, inflammatory disease, UV-light, etc. [51].
In fact, CRP’s main function is to increase in response to infection and to help remove microbes and abnormal cells from the body. Read more about health conditions associated with high CRP here.
Takeaway
Since CRP is a marker of chronic inflammation, it should come as no surprise that dietary and lifestyle factors that increase stress and worsen inflammation also raise CRP. Many of these factors are all too often overlooked. Among the preventable causes of high CRP levels, poor sleep, chronic exhaustion, and smoking are the main lifestyle-related ones. Not sleeping enough, sleeping too much, and irregular, low-quality sleep all increase CRP; stressing about your income, relationships, or work has the same effect. Additionally, spending time at very high altitudes or in extremely cold environments raises CRP, while short-term stays at moderate altitudes decrease it. Not getting enough sun (or dietary vitamin D) is another possible cause of high CRP. Your diet can have a strong influence on your CRP levels. Diets high in saturated and trans fats and low in vitamins A and K increase CRP levels and inflammation. Hormonal imbalances can also cause high CRP. High leptin and estrogen are among the potential culprits.
