Table 3.
Adjusted Hazard Ratios for Cardiovascular Disease in Children with ADHD
| Variable | Hazard ratio | 95% Confidence interval | |
|---|---|---|---|
| Medicine dosage (12 months before the cardiovascular event) | |||
| No stimulant medication(reference) | 1 | ||
| Dosage <15 mg methylphenidate | 1.43 | 0.57 | 3.59 |
| Dosage 15–30 mg methylphenidate | 1.67 | 0.84 | 3.32 |
| Dosage >30 mg methylphenidate | 2.24 | 1.20 | 4.21 |
| Childa | |||
| Male (0/1) | 0.71 | 0.45 | 1.11 |
| 5 min Apgar score | 0.50 | 0.04 | 6.02 |
| Birth weight <1500 g | 0.33 | 0.04 | 2.71 |
| Birth weight 1500–2500 g | 1.07 | 0.52 | 2.19 |
| Birth weight >2500 g (reference) | 1.00 | ||
| Gestation length (weeks) | 1.00 | 0.94 | 1.07 |
| Child health missing | 0.67 | 0.05 | 9.43 |
| Complications at birth | 1.21 | 0.80 | 1.85 |
| Heart disease at birth (Q20–28) | 4.57 | 2.29 | 9.10 |
| Cardiovascular disease before age 5 | 2.77 | 1.22 | 6.32 |
| Diabetes | 38.65 | 4.44 | 336.78 |
| Treatment with heart medication before age 5 | 0.86 | 0.13 | 5.70 |
| Any comorbid psychiatric condition | 1.20 | 0.68 | 2.13 |
| Number of comorbid psychiatric diagnoses | 1.21 | 1.05 | 1.39 |
| Comorbid affective or anxiety disorder | 1.52 | 0.87 | 2.64 |
| Number of injuries before age 5 | 0.97 | 0.82 | 1.14 |
| Number of contacts with a hospital before age 5 | 1.04 | 1.02 | 1.07 |
| Number of visits to the emergency ward before age 5 | 1.11 | 0.98 | 1.27 |
| Mothera | |||
| Age | 1.00 | 0.95 | 1.04 |
| Educational level, high school or less | 1.00 | 0.54 | 1.84 |
| Length of education (years) | 1.04 | 0.92 | 1.19 |
| Unemployed <13 weeks | 0.90 | 0.46 | 1.78 |
| Unemployed 13–26 weeks | 0.70 | 0.27 | 1.79 |
| Unemployed >26 weeks (reference) | 1 | ||
| Employed in November | 1.16 | 0.71 | 1.91 |
| Psychiatric diagnoses | 0.88 | 0.46 | 1.67 |
| Cardiovascular disease | 1.31 | 0.61 | 2.83 |
| Respiratory disease | 0.66 | 0.38 | 1.13 |
| Smoking during pregnancy | 1.50 | 0.59 | 3.83 |
| Data on smoking missing | 1.29 | 0.61 | 2.76 |
| Diabetes | 0.80 | 0.10 | 6.39 |
| Cardiovascular medication (ATC-C code) | 0.81 | 0.38 | 1.74 |
| Data on mother missing | 2.66 | 0.37 | 19.22 |
| Fathera | |||
| Age | 1.02 | 0.99 | 1.04 |
| Educational level, high school or less | 1.02 | 0.54 | 1.95 |
| Length of education (years) | 0.98 | 0.85 | 1.13 |
| Unemployed <13 weeks | 1.09 | 0.46 | 2.57 |
| Unemployed 13–26 weeks | 1.86 | 0.64 | 5.41 |
| Unemployed >26 weeks (reference) | 1 | ||
| Employed in November | 1.64 | 0.82 | 3.29 |
| Psychiatric diagnosis | 0.92 | 0.46 | 1.84 |
| Cardiovascular disease | 0.78 | 0.33 | 1.85 |
| Respiratory disease | 0.91 | 0.51 | 1.60 |
| Diabetes | 1.95 | 0.46 | 8.25 |
| Cardiovascular medication (ATC-C code) | 2.17 | 0.96 | 4.92 |
| Data on father missing | 1.75 | 0.25 | 12.23 |
| Regionsa | |||
| Northern Jutland | 0.68 | 0.25 | 1.83 |
| Central Jutland | 0.88 | 0.52 | 1.49 |
| Southern Jutland | 0.72 | 0.39 | 1.32 |
| Zealand | 1.37 | 0.78 | 2.41 |
| Copenhagen area (reference) | 1 | ||
Observations: Days 23,736,162 /Individuals 8295.
Bold indicates a significant difference between the never and ever stimulant group at the 5% level.
a
Covariates measured when the child was 4 years of age, unless otherwise specified.
ADHD, attention-deficit/hyperactivity disorder; ATC-C, anatomical therapeutic chemical code C.