Characterizing the Role of Pain Sensitivity in Acute to Persistent Low Back Pain

The specific aims (SA) of the proposed study are to:

Specific Aim 1. Characterize (A) the differences in pain sensitivity between incident cases and controls at low back pain onset and (B) changes in pain sensitivity over time in incident cases.

H1.A Incident cases will have increased pain sensitivity compared with controls at low back pain onset.

H1.B Incident cases will have increased pain sensitivity over time.

Specific Aim 2. Compare (A) genetic polymorphisms at low back pain onset between incident cases and controls and mRNA expression of candidate genes at LBP onset and at 6 weeks between incident cases and controls; and (B) differential expression levels of candidate genes over time in incident cases.

H2.A Incident cases will have a higher frequency of polymorphisms and differential expression levels of candidate genes at low back pain onset compared with controls.

H2.B Examine expression levels of candidate genes over time in incident cases.

Specific Aim 3. Determine the contribution of enhanced pain sensitivity, cofactors (clinical/psychosocial/environmental), genetic polymorphisms, and mRNA expression of candidate genes on the risk of persistent low back pain.

Inclusion criteria

• 18-50 years of age;
• diagnosed with an acute episode of nonspecific LBP present for >24 hours but <4 weeks duration and preceded by at least 1 pain-free month; and
• comprehend English

Exclusion criteria

• <18 or >50 years of age;
• chronic pain at another site or associated with a painful condition (eg., fibromyalgia, neuropathy, rheumatoid arthritis);
• previous spinal surgery;
• presence of neurological deficits;
• history of comorbidities that affect sensorimotor function (eg., multiple sclerosis, spinal cord injury, diabetes); and
• untreated psychological disorders (major depression, bipolar disorder, schizophrenia)