Cervical flexion posture during smartphone use was not a risk factor for neck pain, but low sleep quality and insufficient physical activity were: a longitudinal investigation

Key points

1. 01This is the first longitudinal study to objectively measure cervical flexion angle while texting and follow people for new neck pain.
2. 02Neck flexion angle during smartphone use, whether standing or sitting, was not linked to developing neck pain or to how often it occurred.
3. 03Low sleep quality and insufficient physical activity were the factors that increased the chance of neck pain.
4. 04The findings challenge the popular belief that bending the neck to use a phone causes neck pain.
5. 05Neck pain appears to be driven by a mix of lifestyle and psychosocial factors rather than posture alone.

How it was conducted

Design

Longitudinal observational study with 12-month follow-up, following STROBE guidelines

Participants

457 adults aged 18 to 65 without neck pain at baseline, recruited in Rio de Janeiro, Brazil

Exposure measure

Cervical flexion angle while texting, measured objectively at baseline with a CROM inclinometer in standing and sitting positions

Outcomes

Point prevalence and frequency of neck pain at one year, by phone or text contact

Analysis

Four multiple logistic regression models adjusting for age, sex, smartphone use time, dependence, anxiety, depression, physical activity, and sleep quality

What they found

• 396 of 457 participants (87%) completed the one-year follow-up, and 40 (10%) reported neck pain at reassessment.
• Standing cervical flexion angle was not associated with neck pain prevalence (OR 1.01; 95% CI 0.97, 1.04) or frequency (OR 1.01; 95% CI 0.99, 1.03).
• Sitting cervical flexion angle was not associated with neck pain prevalence (OR 1.01; 95% CI 0.98, 1.04) or frequency (OR 1.00; 95% CI 0.99, 1.02).
• Low sleep quality increased the chance of neck pain (OR 1.76; 95% CI 1.17, 2.63) and its frequency (OR 1.55; 95% CI 1.21, 1.99).
• Insufficiently active participants had higher odds of neck pain than active participants (OR 2.41; 95% CI 1.03, 5.65); sedentary participants showed a non-significant suggestion of higher risk (OR 2.39; 95% CI 0.83, 6.86).
• Mean cervical flexion angle while texting was 34 degrees (SD 12) standing and 36 degrees (SD 14) sitting.

Limitations

• The study did not distinguish between acute and chronic neck pain, and used a single yes or no question about pain on the follow-up day.
• The average age was relatively young (27 years), so results may not generalize to older adults.
• Follow-up occurred during the 2020 COVID-19 pandemic, which may have made participants more sedentary.
• It is unknown whether the posture measured during the test task reflects each person's habitual texting posture.

Why it matters

For patients

You do not need to fear that looking down at your phone is causing neck pain, but improving your sleep and staying physically active may help protect against it.

For clinicians

Counsel patients on sleep quality and physical activity rather than focusing on smartphone posture correction when addressing neck pain risk.

For readers

Adds longitudinal evidence that text neck posture is not a risk factor for neck pain, shifting attention toward modifiable lifestyle factors.