Higher Calories Burned Predicts Slightly Higher Psoriasis Severity for Population

Higher Calories Burned Predicts Slightly Higher Psoriasis Severity for Population

Contents

Variables

A
Calories Burned 878
A
Psoriasis Severity 1201

Categories

A
Physical Activity 1719
A
Symptoms 13336

Actions

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Join Study
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Your Data

Tags

Medium Confidence
Very Weak Effect Size
Positive Relationship
Population Study
cause image gauge image effect image
Participants reported a 6.7% average increase in Psoriasis Severity following above average Calories Burned.

Abstract

Psoriasis Severity was generally 4.95% higher than average after 462 kilocalories of Calories Burned per 7 days.

Aggregated data from 3 study participants suggests with a MEDIUM degree of confidence (p=0.163, 95% CI -0.068 to 0.38) that Calories Burned has a weakly positive predictive relationship (R=0.156) with Psoriasis Severity.

The highest quartile of Psoriasis Severity measurements were observed following an average 1.5 kilocalories Calories Burned per day.

The lowest quartile of Psoriasis Severity measurements were observed following an average 2100 kilocalories of Calories Burned per day.

After an onset delay of 0 seconds, Psoriasis Severity is typically 4% lower than average over the 7 days following around 2100 kilocalories of Calories Burned Calories Burned.

Keywords: Calories Burned, Psoriasis Severity, N-of-1 trials, real-world evidence, causal inference, observational study

Preliminary: Based on 3 participants. Results may change as more data is collected.

Results

Primary Findings

Analysis of 257 paired observations from 3 participants revealed a minimal improvement in Psoriasis Severity following above-average Calories Burned exposure.

+5.0%
Change from Baseline
Minimal effect on Psoriasis Severity
0.30
Predictor Impact Score
Weak evidence for causal relationship

Supporting Statistics

Medium
Confidence
0.156
Correlation (r)
p = 0.672
Significance
z = 0.35
Effect Magnitude
φ = 1.00
Temporality

What This Means

When participants had above-average Calories Burned:

  • Psoriasis Severity increased by 5.0% on average
  • Temporal analysis supports Calories Burned as the predictor (not the outcome)

Interpreting the Predictor Impact Score

The Predictor Impact Score (PIS) integrates multiple Bradford Hill causal criteria into a single metric. Use this guide to interpret the score:

PIS Range Interpretation Recommended Action
≥ 0.5 Strong evidence High priority for RCT validation
0.3 - 0.5 Moderate evidence Consider for experimental investigation
0.1 - 0.3 Weak evidence Monitor for additional data
< 0.1 Insufficient evidence Low priority; may be noise

Note: PIS is a prioritization heuristic, not proof of causation. High scores indicate relationships worth investigating, not confirmed causal effects. With only 3 participants, these scores are preliminary and will become more reliable as additional data is collected.

Optimal Daily Values (Precision Dosing)

Based on the observed relationship, we can estimate the predictor values associated with the best and worst outcomes. These values enable personalized dosing recommendations.

⚠️ Preliminary Data: With 3 participants and 257 observations, these optimal values are preliminary estimates. As more data is collected, precision will improve significantly.

462.3 kcal
Value Predicting Higher Psoriasis Severity
Average Calories Burned when Psoriasis Severity exceeded its mean
462.3 kcal
Value Predicting Lower Psoriasis Severity
Average Calories Burned when Psoriasis Severity was below its mean

What This Suggests

Psoriasis Severity tended to be highest when Calories Burned was around 462.3 kcal.

Important: These values reflect correlations, not guaranteed causal effects. Individual responses may vary. Use as a starting point for personal experimentation, not as a definitive prescription. Consult healthcare providers before making treatment decisions.

Population Correlation

Calories Burned Distribution

Psoriasis Severity Distribution

Relationship Analysis

Statistical Summary

Relationship Statistics

Property Value
Cause Variable Name Calories Burned
Effect Variable Name Psoriasis Severity
Sinn Predictive Coefficient 0.29964005634282
Confidence Level MEDIUM
Confidence Interval 0.22433
Forward Pearson Predictive Coefficient 0.1561
Critical T Value 1.661
Total Calories Burned Over Previous 7 days Before ABOVE Average Psoriasis Severity 1.5 kilocalories
Total Calories Burned Over Previous 7 days Before BELOW Average Psoriasis Severity 2100 kilocalories
Duration of Action 7 days
Effect Size weakly positive
Number of Paired Measurements 257
Optimal Pearson Product 0.040057530462628
P Value 0.16329
Statistical Significance 0.6722
Strength of Relationship 0.22433
Study Type population
Analysis Performed At 2026-01-04
Number of Participants 3

Calories Burned Info

Property Value
Variable Name Calories Burned
Aggregation Method SUM
Analysis Performed At 2020-09-23
Duration of Action 7 days
Kurtosis 10.719482104079
Maximum Allowed Value 20000 kilocalories
Mean 1693.6119981094 kilocalories
Median 1643.7344918892 kilocalories
Minimum Allowed Value 100 kilocalories
Number of Aggregate Predictors 667
Number of Aggregate Outcomes 211
Number of Measurements 122895
Number of Measurements (including those generated by tagged, joined, or child variables) 21949
Public true
Onset Delay 0 seconds
Standard Deviation 420.78331639612
Unit Kilocalories
User Variables 393
UPC 0
Variable Category Physical Activity
Variable ID 1280
Variance 236738.41913029

Psoriasis Severity Info

Property Value
Variable Name Psoriasis Severity
Aggregation Method MEAN
Analysis Performed At 2022-10-02
Duration of Action 24 hours
Kurtosis 1.7521273313558
Maximum Allowed Value 5 out of 5
Mean 2.8263571428571 out of 5
Median 2.7857142857143 out of 5
Minimum Allowed Value 1 out of 5
Number of Aggregate Predictors 1008
Number of Aggregate Outcomes 193
Number of Measurements 1787
Number of Measurements (including those generated by tagged, joined, or child variables) 1787
Public true
Onset Delay 0 seconds
Standard Deviation 0.33908557762432
Unit 1 to 5 Rating
User Variables 19
UPC 0
Variable Category Symptoms
Variable ID 1421
Variance 0.42202550439075

Introduction

Background

Calories Burned (Physical Activity) and Psoriasis Severity (Symptoms) are both important factors in understanding human health and well-being. This study investigates the relationship between these two variables using real-world observational data.

Traditional randomized controlled trials (RCTs), while the gold standard for causal inference, are often impractical, expensive, or unethical for studying many health relationships. Aggregated N-of-1 observational studies offer a complementary approach that leverages within-subject comparisons across large populations to identify meaningful patterns.

Research Question

Does Calories Burned affect Psoriasis Severity?

Additionally, we seek to determine:

  1. What is the direction and magnitude of any effect?
  2. How confident can we be in this relationship based on the available data?
  3. What are the optimal levels of Calories Burned for maximizing Psoriasis Severity?

Study Objective

The objective of this study is to determine the nature of the relationship (if any) between Calories Burned and Psoriasis Severity. Additionally, we attempt to determine the Calories Burned values most likely to produce optimal Psoriasis Severity values.

Study Overview

This is a population-level observational study using aggregated N-of-1 methodology. By aggregating individual N-of-1 experiments, we can identify population-level patterns while accounting for the substantial individual variation that exists in most health relationships. Effect sizes are reported as percent change from baseline, enabling intuitive interpretation and comparison across different measures.

Full Methodology: Framework for Real-World Evidence-Based Pharmacovigilance: Aggregated N-of-1 Trials for Quantifying Treatment Effects

Discussion

Interpretation of Findings

Participants experienced a 5.0% improvement in Psoriasis Severity following above-average Calories Burned exposure. The Predictor Impact Score (PIS) of 0.30 indicates weak evidence for a causal relationship.

Statistical Significance

Using a two-tailed t-test with alpha = 0.05, it was determined that the change in Psoriasis Severity is statistically significant at a 95% confidence interval. The p-value of 0.6722 indicates there is less than a 67.22% probability that this result occurred by chance.

After treatment, a 6.7% increase (0.107 out of 5) from the mean baseline 2.29 out of 5 was observed. The relative standard deviation at baseline was 26.25%. The observed change was 0.34793 times the standard deviation.

A common rule of thumb considers a change greater than twice the baseline standard deviation on two separate pre-post experiments may be considered significant. This occurrence would have only a 5% likelihood of resulting from random fluctuation (a p-value < 0.05).

T-Test Details
Observed t-value: 2.270
Critical t-value: 1.661

Since t = 2.27 > 1.66, we reject the null hypothesis.

Biological Plausibility

A plausible bio-chemical mechanism between predictor and outcome is critical for interpreting observational findings. This is where human judgment excels beyond statistical analysis.

Based on community responses so far, 1 person feels that there is a plausible mechanism of action and 0 feel that any relationship observed between Calories Burned and Psoriasis Severity is coincidental.

Bradford Hill Criteria Assessment

The Bradford Hill criteria provide a framework for assessing causality in observational studies. Our methodology operationalizes six of the nine criteria through the Predictor Impact Score (PIS):

Criterion How Addressed Metric
Strength Effect size magnitude Percent change from baseline (Δ%), z-score
Consistency Cross-participant replication Number of users (N), number of pairs (n)
Temporality Predictor precedes outcome Temporality factor (φ), onset delay (δ > 0)
Biological Gradient Dose-response relationship Gradient coefficient (φgradient)
Plausibility Biological mechanism assessment Community votes on mechanism plausibility
Specificity Category appropriateness Interest factor (finterest)

Predictor Impact Score (PIS)

The PIS integrates multiple Bradford Hill criteria into a composite metric quantifying how reliably a predictor affects an outcome. Higher scores indicate stronger evidence:

Population-Level PIS:

$$\text{PIS}_{\text{agg}} = |r_{\text{forward}}| \cdot w \cdot \phi_{\text{users}} \cdot \phi_{\text{pairs}} \cdot \phi_{\text{change}} \cdot \phi_{\text{gradient}}$$

Where φ-factors are saturation functions approaching 1 as evidence accumulates:

  • φusers = 1 - e-N/10 (user saturation)
  • φpairs = 1 - e-n/nsig (pair saturation)
  • φchange = 1 - e-Δspread/Δsig (effect spread saturation)
  • w = weighted average of plausibility votes

Temporality Assessment

We assess evidence for correct causal direction using the temporality factor:

$$\phi_{\text{temporal}} = \frac{|r_{\text{forward}}|}{|r_{\text{forward}}| + |r_{\text{reverse}}|}$$

Values approaching 1 indicate the predictor precedes the outcome (supporting causation); values near 0.5 suggest ambiguous directionality; values near 0 suggest reverse causation or confounding by indication.

Limitations

As with any observational study, correlation does not prove causation. Key limitations include:

  • Unmeasured confounders: Variables not tracked may influence results
  • Self-selection bias: Health trackers may differ from the general population
  • Measurement error: Self-reported data may contain recall bias
  • Confounding by indication: Sicker individuals may use more treatments

However, within-subject comparison and temporal precedence analysis partially mitigate these limitations. If the relationship is merely coincidental, as participants independently modify their Calories Burned values, the observed strength will decline over time. Spurious correlations naturally dissipate as more data is collected.

Future Directions

Future research should examine:

  • Subgroup analyses to identify individual differences in response
  • Potential confounders and mediators of the observed relationship
  • Optimal dosing and timing for Calories Burned
  • Confirmation through prospective or randomized designs
  • Biological mechanisms underlying the observed effects

Conclusion

📊 Preliminary Findings: With 3 participants, these results are based on limited data. Effect sizes and confidence will improve as more participants contribute data. Consider these findings directional rather than definitive.

Above-average Calories Burned was associated with a 5.0% improvement in Psoriasis Severity—a minimal effect. The Predictor Impact Score of 0.30 indicates this relationship is warranting continued monitoring.

Bottom Line: Based on a PIS of 0.30 and a 5.0% effect size, this relationship shows weak evidence. Additional observational data is recommended before investing in experimental validation. Note: These conclusions may strengthen or change direction as more data is collected.

These findings contribute to our understanding of how Calories Burned may influence Psoriasis Severity in real-world conditions. While preliminary, these results may inform future research directions. As more participants contribute data, the reliability and precision of these findings will improve substantially.

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Methods

Study Design

This study is based on data donated by 3 participants. Thus, the study design is equivalent to the aggregation of 3 separate n=1 observational natural experiments.

This within-subject design is powerful because it controls for all stable individual characteristics (genetics, baseline health status, socioeconomic factors) that might otherwise confound the relationship between variables.

Data Analysis

Temporal Assumptions

The analysis incorporates temporal assumptions about the relationship between variables:

  • Onset Delay: It was assumed that 0 seconds would pass before a change in Calories Burned would produce an observable change in Psoriasis Severity.
  • Duration of Action: It was assumed that Calories Burned could produce an observable change in Psoriasis Severity for as much as 7 days after the stimulus event.

Statistical Methods

For each participant, we calculated the Pearson correlation coefficient between Calories Burned values and subsequent Psoriasis Severity values. Individual correlations were then aggregated using Fisher's z-transformation to produce a population-level estimate:

Individual Correlation:

$$r_i = \frac{\sum(x_{ij} - \bar{x}_i)(y_{ij} - \bar{y}_i)}{\sqrt{\sum(x_{ij} - \bar{x}_i)^2 \sum(y_{ij} - \bar{y}_i)^2}}$$

Fisher's Z-Transformation:

$$z_i = \frac{1}{2} \ln\left(\frac{1 + r_i}{1 - r_i}\right)$$

Aggregated Correlation:

$$\bar{r} = \tanh(\bar{z}) \quad \text{where} \quad \bar{z} = \frac{1}{N}\sum_{i=1}^{N} z_i$$

Effect Size Calculation

Effect sizes are reported as percent change from baseline. For each participant, we compare the outcome following above-average predictor values to the overall baseline outcome:

$$\Delta\%_{\text{baseline}} = \frac{\bar{O}_{\text{follow-up}} - \bar{O}_{\text{baseline}}}{\bar{O}_{\text{baseline}}} \times 100$$

Effect Magnitude (Z-Score)

To assess effect magnitude relative to natural variability, we calculate the z-score:

$$z = \frac{|\Delta\%_{\text{baseline}}|}{\text{RSD}_{\text{baseline}}}$$

where RSDbaseline is the relative standard deviation of outcome during baseline period

A z-score > 2 indicates statistical significance (p < 0.05), meaning the observed change exceeds typical baseline fluctuation and is unlikely due to random variation.

Statistical Significance

Correlation significance is assessed using a two-tailed t-test:

$$t = \frac{r\sqrt{n-2}}{\sqrt{1-r^2}}$$

We reject the null hypothesis (ρ = 0) at α = 0.05 when |t| exceeds the critical value, providing statistical evidence that the observed relationship is not due to chance.

Data Sources

Calories Burned data was primarily collected using Fitbit. Fitbit makes activity tracking easy and automatic.

Psoriasis Severity data was primarily collected using QuantiModo. QuantiModo allows you to easily track mood, symptoms, or any outcome you want to optimize in a fraction of a second. You can also import your data from over 30 other apps and devices. QuantiModo then analyzes your data to identify which hidden factors are most likely to be influencing your mood or symptoms.

Data Quality

Data quality measures were applied to ensure reliable results:

  • Minimum Data Requirement: Only participants with sufficient paired observations were included in the analysis.
  • Outlier Handling: Extreme values were winsorized to reduce the influence of measurement errors.
  • Missing Data: Days with missing values were handled using appropriate filling strategies based on the variable type.
  • Test User Exclusion: Test accounts and invalid users were excluded from all analyses.

Principal Investigator

Program & Methods

Mike P. Sinn
Sinn, M. P.

Designed and implemented data collection, aggregation, causal inference pipeline, and automated study generation framework. Developed the Predictor Impact Score methodology operationalizing Bradford Hill criteria for ranking causal relationships in observational data. When he tells people this at parties, they usually say they have to go check on their car.

Individual study outputs are automated, reproducible, and open to external audit. (Which I would seriously recommend.)

Contact

Cite This Study

APA Format
Sinn, M. P. (2026). Causal Analysis: Does Calories Burned Affect Psoriasis Severity?. The Journal of Citizen Science. https://studies.crowdsourcingcures.org/study/cause-1280-effect-1421-population-study
BibTeX 
@misc{sinn_cause_1280_effect_1421_population_study_2026,
  author = {Sinn, Mike P.},
  title = {Causal Analysis: Does Calories Burned Affect Psoriasis Severity?},
  year = {2026},
  publisher = {The Journal of Citizen Science},
  url = {https://studies.crowdsourcingcures.org/study/cause-1280-effect-1421-population-study},
  note = {Accessed: January 6, 2026}
}
Chicago/Turabian
Sinn, Mike P. "Causal Analysis: Does Calories Burned Affect Psoriasis Severity?." The Journal of Citizen Science. Accessed January 6, 2026. https://studies.crowdsourcingcures.org/study/cause-1280-effect-1421-population-study.
Harvard
Sinn, M.P., 2026. Causal Analysis: Does Calories Burned Affect Psoriasis Severity?. [Aggregated N-of-1 Study] The Journal of Citizen Science. Available at: https://studies.crowdsourcingcures.org/study/cause-1280-effect-1421-population-study [Accessed January 6, 2026].

Study Type: Aggregated N-of-1 Observational Mega-Study
Evidence Level: Level II (Real-World Evidence)
Methodology: Bradford Hill Criteria with Predictor Impact Score (PIS)

References

This framework was originally developed in 2013 based on the Bradford Hill criteria. Subsequent literature has independently validated similar approaches to causal inference from observational data:

  1. Hill, A.B. (1965). The environment and disease: association or causation? Proceedings of the Royal Society of Medicine, 58(5), 295-300. [Bradford Hill criteria]
  2. Lillie, E.O., et al. (2011). The n-of-1 clinical trial: the ultimate strategy for individualizing medicine? Personalized Medicine, 8(2), 161-173. [N-of-1 methodology]
  3. Pearl, J. (2009). Causality: Models, Reasoning, and Inference . Cambridge University Press. [Causal inference]
  4. Hernán, M.A., & Robins, J.M. (2020). Causal Inference: What If . Chapman & Hall/CRC. [Free textbook]
  5. FDA (2018). Framework for FDA's Real-World Evidence Program . U.S. Food and Drug Administration. [Regulatory context]
  6. Duan, N., et al. (2013). Single-patient (n-of-1) trials: a pragmatic clinical decision methodology . Journal of Clinical Epidemiology, 66(8), S21-S28.
  7. Platt, R., et al. (2018). The FDA Sentinel Initiative—an evolving national resource . New England Journal of Medicine, 379(22), 2091-2093.

This information is for research and educational purposes only, not medical advice. Consult a healthcare provider before making health decisions. Terms of Service

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